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Forests
Volume 9
Issue 3
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Forests, Volume 9, Issue 3 (March 2018) – 59 articles

Cover Story (view full-size image): After patch- or clear-cut harvesting, the stumps represent a legacy of the trees that once stood there. In this research, we developed and tested a novel method to detect, segment, classify and measure tree stumps from unmanned aerial vehicle (UAV) imagery. This was done to assess how much stand information could be regenerated. Our trials show that it is indeed possible to capture a range of information on the basis of images from inexpensive UAVs. This information may be useful for a variety of applications. Among these, the possibility to obtain information on the spatial distribution of pathogens such as root- and butt-rot within a stand has great potential in providing decision support in mitigating the negative effects of these pathogens in future tree generations. View this paper
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14 pages, 6179 KiB  
Article
De Novo Sequencing and Assembly Analysis of Transcriptome in Pinus bungeana Zucc. ex Endl.
by Qifei Cai, Bin Li, Furong Lin, Ping Huang, Wenying Guo and Yongqi Zheng
Forests 2018, 9(3), 156; https://doi.org/10.3390/f9030156 - 20 Mar 2018
Cited by 8 | Viewed by 4289
Abstract
To enrich the molecular data of Pinus bungeana Zucc. ex Endl. and study the regulating factors of different morphology controled by apical dominance. In this study, de novo assembly of transcriptome annotation was performed for two varieties of Pinus bungeana Zucc. ex Endl. [...] Read more.
To enrich the molecular data of Pinus bungeana Zucc. ex Endl. and study the regulating factors of different morphology controled by apical dominance. In this study, de novo assembly of transcriptome annotation was performed for two varieties of Pinus bungeana Zucc. ex Endl. that are obviously different in morphology. More than 147 million reads were produced, which were assembled into 88,092 unigenes. Based on a similarity search, 11,692 unigenes showed significant similarity to proteins from Picea sitchensis (Bong.) Carr. From this collection of unigenes, a large number of molecular markers were identified, including 2829 simple sequence repeats (SSRs). A total of 158 unigenes expressed differently between two varieties, including 98 up-regulated and 60 down-regulated unigenes. Furthermore, among the differently expressed genes (DEGs), five genes which may impact the plant morphology were further validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The five genes related to cytokinin oxidase/dehydrogenase (CKX), two-component response regulator ARR-A family (ARR-A), plant hormone signal transduction (AHP), and MADS-box transcription factors have a close relationship with apical dominance. This new dataset will be a useful resource for future genetic and genomic studies in Pinus bungeana Zucc. ex Endl. Full article
(This article belongs to the Special Issue Genetics and Genomics of Forest Trees)
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18 pages, 6042 KiB  
Article
Development of an Integrated DBH Estimation Model Based on Stand and Climatic Conditions
by Dongfan Piao, Moonil Kim, Go-Mee Choi, Jooyeon Moon, Hangnan Yu, Woo-Kyun Lee, Sonam Wangyel Wang, Seong Woo Jeon, Yowhan Son, Yeong-Mo Son and Guishan Cui
Forests 2018, 9(3), 155; https://doi.org/10.3390/f9030155 - 20 Mar 2018
Cited by 12 | Viewed by 4732
Abstract
Using Korean National Forest Inventory (NFI) data, our study developed a model to estimate stand mean diameter at breast height (DBH) reflecting the influence of site and climate factors on forest growth for the major tree species in South Korea. A DBH estimation [...] Read more.
Using Korean National Forest Inventory (NFI) data, our study developed a model to estimate stand mean diameter at breast height (DBH) reflecting the influence of site and climate factors on forest growth for the major tree species in South Korea. A DBH estimation model was developed using stand-level variables (stand age, site index and number of trees per hectare) as independent factors. The spatial autocorrelation of residuals of the model was identified using semi-variogram analysis for each tree species. Further, a residual model, in which residuals were estimated by climatic factors (mean temperature, sum temperature in the growing season and precipitation), was developed assuming that the spatial autocorrelation of residuals reflects the differences in regional climatic conditions. Linear regression analysis showed that residuals of all tree species were significantly correlated with temperature and precipitation. The DBH and residual models were integrated to estimate the current DBH under different climatic factors (temperature and precipitation) and stand-level variables. This model had high reliability (R2 = 0.74–0.79), and no obvious dependencies or patterns in residuals were noted. Our results indicated that temperature increases caused by climate change would negatively affect the DBH estimate of coniferous trees, but not of oak species. Full article
(This article belongs to the Special Issue Simulation Modeling of Forest Ecosystems)
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17 pages, 1197 KiB  
Article
Willow Short Rotation Coppice Trial in a Former Mining Area in Northern Spain: Effects of Clone, Fertilization and Planting Density on Yield after Five Years
by María Castaño-Díaz, Marcos Barrio-Anta, Elías Afif-Khouri and Asunción Cámara-Obregón
Forests 2018, 9(3), 154; https://doi.org/10.3390/f9030154 - 20 Mar 2018
Cited by 23 | Viewed by 4231
Abstract
A willow short rotation coppice (SRC) trial was conducted on former mining land in northern Spain over a period of five years, with the purpose of evaluating the effects on yield of two planting densities (9876 and 14,815 cuttings ha−1), three [...] Read more.
A willow short rotation coppice (SRC) trial was conducted on former mining land in northern Spain over a period of five years, with the purpose of evaluating the effects on yield of two planting densities (9876 and 14,815 cuttings ha−1), three treatments (control, two levels of nitrogen, phosphorus and potassium compound fertilizer (NPK) plus weed control) and three willow clones (Björn, Inger, Olof). The area was subsoiled, ploughed, harrowed and fertilized with NPK before trial establishment. A randomized block design was applied, with three replications of each treatment in a total of 54 plots, each of an area of 400 m2. The effects of the interactions between the various factors on yield and other growth parameters were also studied. The clone factor significantly affected the number of shoots per stool (greatest for the Inger clone) and the Olof clone, which showed the lowest mortality rate and produced the largest trees and largest quantity of biomass. The combined application of fertilizer and herbicide also significantly increased the values of all response variables considered, except the mortality rate. The planting density did not significantly affect the response variables. Clone × treatment interactions were significant for the shoots per stool, height, diameter and biomass variables, and the Olof clone displayed the highest height and diameter growth and yield. The results obtained in the first rotation indicate that the Olof clone adapted well to the trial conditions and therefore would be appropriate for producing biomass in abandoned mine land in Asturias. These findings will help in the development of strategies for the establishment and management of SRC on marginal land. Full article
(This article belongs to the Section Forest Ecology and Management)
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17 pages, 3064 KiB  
Article
Seasonal Effects on Microbial Community Structure and Nitrogen Dynamics in Temperate Forest Soil
by Tomohiro Yokobe, Fujio Hyodo and Naoko Tokuchi
Forests 2018, 9(3), 153; https://doi.org/10.3390/f9030153 - 19 Mar 2018
Cited by 43 | Viewed by 6335
Abstract
The soil microbial community and nitrogen (N) dynamics change seasonally due to several factors. The microbial community structure (MCS) can regulate N dynamics. However, there is insufficient information on seasonal changes in MCS and the relationship between MCS and N dynamics. We investigated [...] Read more.
The soil microbial community and nitrogen (N) dynamics change seasonally due to several factors. The microbial community structure (MCS) can regulate N dynamics. However, there is insufficient information on seasonal changes in MCS and the relationship between MCS and N dynamics. We investigated MCS and N dynamics in forest soils with two different fertilities throughout a year. MCS, measured with phospholipid fatty acid (PLFA) analysis, showed a consistent seasonal trend, regardless of the fertility. Microbial indices (particularly the Saturated-/monounsaturated-PLFA ratio; Sat/mono) indicated a major PLFA shift among seasons, with temperature likely the most important factor. The fungal-/bacterial-PLFA ratio in the dormant season (December–April) was approximately 1.3 times greater than in the growing season (June–November). The trend in N dynamics showed that in summer (June–August), the gross N mineralization potential was greater than immobilization, whereas in winter (December–April), immobilization was dominant. The net mineralization potential in the growing season was approximately 1.6 times higher than in the dormant season. Moreover, a relationship was found between Sat/mono and N transformation potentials. We highlight the microbial sensitivity to seasonal dynamics which can be associated with temperature, as well as carbon and N dynamics. Full article
(This article belongs to the Special Issue Carbon, Nitrogen and Phosphorus Cycling in Forest Soils)
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17 pages, 3201 KiB  
Article
Overstory Structure and Surface Cover Dynamics in the Decade Following the Hayman Fire, Colorado
by Paula J. Fornwalt, Camille S. Stevens-Rumann and Byron J. Collins
Forests 2018, 9(3), 152; https://doi.org/10.3390/f9030152 - 17 Mar 2018
Cited by 15 | Viewed by 4349
Abstract
The 2002 Hayman Fire burned with mixed-severity across a 400-ha dry conifer study site in Colorado, USA, where overstory tree and surface cover attributes had been recently measured on 20 0.1-ha permanent plots. We remeasured these plots repeatedly during the first post-fire decade [...] Read more.
The 2002 Hayman Fire burned with mixed-severity across a 400-ha dry conifer study site in Colorado, USA, where overstory tree and surface cover attributes had been recently measured on 20 0.1-ha permanent plots. We remeasured these plots repeatedly during the first post-fire decade to examine how the attributes changed through time and whether changes were influenced by fire severity. We found that most attributes were temporally dynamic and that fire severity shaped their dynamics. For example, low-severity plots experienced a modest reduction in live overstory density due to both immediate and delayed tree mortality, and no change in live overstory basal area through time; in contrast, high-severity plots experienced an immediate and total loss of live overstory density and basal area. Large snag density in low-severity plots did not vary temporally because snag recruitment balanced snag loss; however, in high-severity plots large snag density increased markedly immediately post-fire and then declined by about half by post-fire year ten as snags fell. Mineral soil cover increased modestly immediately post-fire in low-severity plots and substantially immediately post-fire in high-severity plots, but changed little in ensuing years for either severity class. By incorporating pre-fire and repeatedly-measured post-fire data for a range of severities, our study uniquely contributes to the current understanding of wildfire effects in dry conifer forests and should be of interest to managers, researchers, and others. Full article
(This article belongs to the Special Issue Wildland Fire, Forest Dynamics, and Their Interactions)
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25 pages, 4938 KiB  
Article
Topoedaphic and Forest Controls on Post-Fire Vegetation Assemblies Are Modified by Fire History and Burn Severity in the Northwestern Canadian Boreal Forest
by Ellen Whitman, Marc-André Parisien, Dan K. Thompson and Mike D. Flannigan
Forests 2018, 9(3), 151; https://doi.org/10.3390/f9030151 - 17 Mar 2018
Cited by 50 | Viewed by 7117
Abstract
Wildfires, which constitute the most extensive natural disturbance of the boreal biome, produce a broad range of ecological impacts to vegetation and soils that may influence post-fire vegetation assemblies and seedling recruitment. We inventoried post-fire understory vascular plant communities and tree seedling recruitment [...] Read more.
Wildfires, which constitute the most extensive natural disturbance of the boreal biome, produce a broad range of ecological impacts to vegetation and soils that may influence post-fire vegetation assemblies and seedling recruitment. We inventoried post-fire understory vascular plant communities and tree seedling recruitment in the northwestern Canadian boreal forest and characterized the relative importance of fire effects and fire history, as well as non-fire drivers (i.e., the topoedaphic context and climate), to post-fire vegetation assemblies. Topoedaphic context, pre-fire forest structure and composition, and climate primarily controlled the understory plant communities and shifts in the ranked dominance of tree species (***8% and **13% of variance explained, respectively); however, fire and fire-affected soils were significant secondary drivers of post-fire vegetation. Wildfire had a significant indirect effect on understory vegetation communities through post-fire soil properties (**5%), and fire history and burn severity explained the dominance shifts of tree species (*7%). Fire-related variables were important explanatory variables in classification and regression tree models explaining the dominance shifts of four tree species (R2 = 0.43–0.65). The dominance of jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) increased following fires, whereas that of black spruce (Picea mariana (Mill.) BSP.) and white spruce (Picea glauca (Moench) Voss) declined. The overriding importance of site and climate to post-fire vegetation assemblies may confer some resilience to disturbed forests; however, if projected increases in fire activity in the northwestern boreal forest are borne out, secondary pathways of burn severity, fire frequency, and fire effects on soils are likely to accelerate ongoing climate-driven shifts in species compositions. Full article
(This article belongs to the Special Issue Wildland Fire, Forest Dynamics, and Their Interactions)
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15 pages, 1706 KiB  
Article
Community Forestry for Livelihoods: Benefiting from Myanmar’s Mangroves
by Melanie Feurer, David Gritten and Maung Maung Than
Forests 2018, 9(3), 150; https://doi.org/10.3390/f9030150 - 17 Mar 2018
Cited by 36 | Viewed by 8858
Abstract
It is well known that in many rural communities in the developing world, forests, particularly those under community management, are important for people’s livelihoods. However, studies on the contribution of forests to the income of different households within a community are rare, including [...] Read more.
It is well known that in many rural communities in the developing world, forests, particularly those under community management, are important for people’s livelihoods. However, studies on the contribution of forests to the income of different households within a community are rare, including the poorest households and how non-members of the community forestry user group (CFUG) benefit from those resources. This paper compares livelihood strategies and the use of a mangrove CF by different community members in Myanmar. Utilizing a livelihoods approach, data were collected through a household survey (n = 110) and various participatory tools. The significance of CF for people’s livelihoods was clearly demonstrated, with as many as 91% of households depending on CF products to varying degrees. Livelihood strategies are largely determined by financial assets and road access. Strategies include large levels of dependence on natural resources such as homegardens and CF. Substantial differences were found for CF’s contribution to total income depending on CF membership (p = 0.004) and wealth (p = 0.022). Non-members benefit mostly through subsistence products. The poorest households were found to get the highest income shares (36%) from CF. This leads to the conclusion that with an inclusive process to membership, CF has the potential to reduce poverty. Full article
(This article belongs to the Section Forest Ecology and Management)
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11 pages, 2482 KiB  
Article
Analysis of Soil Degradation Causes in Phyllostachys edulis Forests with Different Mulching Years
by Jiancheng Zhao, Bo Wang, Qin Li, Hejun Yang and Kang Xu
Forests 2018, 9(3), 149; https://doi.org/10.3390/f9030149 - 16 Mar 2018
Cited by 18 | Viewed by 4211
Abstract
Moso bamboo (Phyllostachys edulis (Carrière) J.Houz.) is famous for its fast growth and biomass accumulation, as well as high annual output for timber and bamboo shoots. Organic mulches are widely used to improve shoots’ production in moso bamboo forests. However, continuous mulching [...] Read more.
Moso bamboo (Phyllostachys edulis (Carrière) J.Houz.) is famous for its fast growth and biomass accumulation, as well as high annual output for timber and bamboo shoots. Organic mulches are widely used to improve shoots’ production in moso bamboo forests. However, continuous mulching management may cause bamboo forest degradation and affect sustainable development. The objective of this study was to identify the degradation mechanism and to provide a theoretical basis for recovery. A complete randomized block design with four treatments was conducted, including mulching for one year (M1), two years (M2), three years (M3) and no-mulching management (NM). Soil nutrient contents, enzyme activities and microbial biomass were determined. With the increase of mulching years, the soil pH value gradually reduced, causing soil acidification, but the content of soil organic matter was inclined to ascend. Soil total nitrogen (TN), total phosphorus (TP) and total potassium (TK) contents showed an increasing trend, and they were significantly higher in mulching stands than those in NM (p < 0.05). Contents of soil available nutrients (AN, AP and AK) increased, then decreased with the increase of mulching years and peaked in M1. With the increase of mulching years, the soil stoichiometry ratio (C/N, C/P and N/P) gradually increased. Soil invertase, urease and acid phosphatase activities presented a single-peak curve and reached the maximum within one year after mulching. Total microbial biomass and that of individual groups changed greatly after mulching. Soil microbial biomass increased first and then decreased, and it was the largest in M1. The fungi:bacteria ratio decreased in the first year and then began to rise, while the aerobic:anaerobic ratio showed the opposite trend. According to the overall results, M3 leads to soil acidification, imbalance of the nutrients’ proportion, abnormal enzyme activity and change of soil microbial flora, and rotated mulching management (mulching one year and then recuperating one year) should be recommended in practice. Full article
(This article belongs to the Section Forest Ecology and Management)
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9 pages, 2363 KiB  
Article
Resolving Variables Influencing the Residence Time of Biomass in the Old-Age Forest across Climate Gradients
by Yangrui Han, Weifeng Wang, Weiyan Zhang, Jun Zhang and Dandan Shan
Forests 2018, 9(3), 148; https://doi.org/10.3390/f9030148 - 16 Mar 2018
Viewed by 3486
Abstract
Standing biomass stocks represent a balance between a number of processes that lead to biomass accumulation or to biomass loss. The average time of biomass residence (ATr) of an ecosystem is the average period of time that carbon is locked up in the [...] Read more.
Standing biomass stocks represent a balance between a number of processes that lead to biomass accumulation or to biomass loss. The average time of biomass residence (ATr) of an ecosystem is the average period of time that carbon is locked up in the living biomass before it is transferred to the litter pool and is an important variable influencing the process leading to biomass loss. Variation in terrestrial ATr with climate is thought to originate from a direct influence of temperature and precipitation on plant mortality. However, variation in ATr may also result from an indirect influence of climate by means of plant age and growing season length. To identify the relative importance of direct and indirect climate effects, we analyzed published data of ecosystem woody biomass and productivity from forest plots across climate gradients, using three approaches: bayesian linear regression, multiple regression, and structural equation modeling. The three approaches provided special insights and they converged in supporting climate as an indirect driver of ATr across climate gradients. Notably, age and growing season length explained most of the variation in ATr, whereas mean annual temperature and precipitation explained almost none, suggesting that climate indirectly influenced ATr. Our analyses provide novel evidence not only supporting that the old-age forests could be a carbon sink with a longer time of biomass residence at a large scale, but also modifying the key drivers of ecosystem processes for vegetation dynamic models. Full article
(This article belongs to the Special Issue Old Growth Temperate and Boreal Forests: Processes, Functions, and Dynamics)
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12 pages, 2416 KiB  
Article
Water Level Controls on Sap Flux of Canopy Species in Black Ash Wetlands
by Joseph Shannon, Matthew Van Grinsven, Joshua Davis, Nicholas Bolton, Nam Jin Noh, Thomas Pypker and Randall Kolka
Forests 2018, 9(3), 147; https://doi.org/10.3390/f9030147 - 16 Mar 2018
Cited by 7 | Viewed by 4808
Abstract
Black ash (Fraxinus nigra Marsh.) exhibits canopy dominance in regularly inundated wetlands, suggesting advantageous adaptation. Black ash mortality due to emerald ash borer (Agrilus planipennis Fairmaire) will alter canopy composition and site hydrology. Retention of these forested wetlands requires understanding black [...] Read more.
Black ash (Fraxinus nigra Marsh.) exhibits canopy dominance in regularly inundated wetlands, suggesting advantageous adaptation. Black ash mortality due to emerald ash borer (Agrilus planipennis Fairmaire) will alter canopy composition and site hydrology. Retention of these forested wetlands requires understanding black ash’s ecohydrologic role. Our study examined the response of sap flux to water level and atmospheric drivers in three codominant species: black ash, red maple (Acer rubrum L.), and yellow birch (Betula alleghaniensis Britt.), in depressional wetlands in western Michigan, USA. The influence of water level on sap flux rates and response to vapor pressure deficit (VPD) was tested among species. Black ash had significantly greater sap flux than non-black ash at all water levels (80–160% higher). Black ash showed a significant increase (45%) in sap flux rates as water levels decreased. Black ash and red maple showed significant increases in response to VPD as water levels decreased (112% and 56%, respectively). Exploration of alternative canopy species has focused on the survival and growth of seedlings, but our findings show important differences in water use and response to hydrologic drivers among species. Understanding how a replacement species will respond to the expected altered hydrologic regimes of black ash wetlands following EAB infestation will improve species selection. Full article
(This article belongs to the Special Issue Understanding and Managing Emerald Ash Borer Impacts on Ash Forests)
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11 pages, 1237 KiB  
Article
Methods to Improve Survival and Growth of Planted Alternative Species Seedlings in Black Ash Ecosystems Threatened by Emerald Ash Borer
by Nicholas Bolton, Joseph Shannon, Joshua Davis, Matthew Van Grinsven, Nam Jin Noh, Shon Schooler, Randall Kolka, Thomas Pypker and Joseph Wagenbrenner
Forests 2018, 9(3), 146; https://doi.org/10.3390/f9030146 - 16 Mar 2018
Cited by 12 | Viewed by 4834
Abstract
Emerald ash borer (EAB) continues to spread across North America, infesting native ash trees and changing the forested landscape. Black ash wetland forests are severely affected by EAB. As black ash wetland forests provide integral ecosystem services, alternative approaches to maintain forest cover [...] Read more.
Emerald ash borer (EAB) continues to spread across North America, infesting native ash trees and changing the forested landscape. Black ash wetland forests are severely affected by EAB. As black ash wetland forests provide integral ecosystem services, alternative approaches to maintain forest cover on the landscape are needed. We implemented simulated EAB infestations in depressional black ash wetlands in the Ottawa National Forest in Michigan to mimic the short-term and long-term effects of EAB. These wetlands were planted with 10 alternative tree species in 2013. Based on initial results in the Michigan sites, a riparian corridor in the Superior Municipal Forest in Wisconsin was planted with three alternative tree species in 2015. Results across both locations indicate that silver maple (Acer saccharinum L.), red maple (Acer rubrum L.), American elm (Ulmus americana L.), and northern white cedar (Thuja occidentalis L.) are viable alternative species to plant in black ash-dominated wetlands. Additionally, selectively planting on natural or created hummocks resulted in two times greater survival than in adjacent lowland sites, and this suggests that planting should be implemented with microsite selection or creation as a primary control. Regional landowners and forest managers can use these results to help mitigate the canopy and structure losses from EAB and maintain forest cover and hydrologic function in black ash-dominated wetlands after infestation. Full article
(This article belongs to the Special Issue Understanding and Managing Emerald Ash Borer Impacts on Ash Forests)
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25 pages, 7172 KiB  
Article
Decadal-Scale Reduction in Forest Net Ecosystem Production Following Insect Defoliation Contrasts with Short-Term Impacts of Prescribed Fires
by Kenneth L. Clark, Heidi J. Renninger, Nicholas Skowronski, Michael Gallagher and Karina V. R. Schäfer
Forests 2018, 9(3), 145; https://doi.org/10.3390/f9030145 - 16 Mar 2018
Cited by 27 | Viewed by 4994
Abstract
Understanding processes underlying forest carbon dynamics is essential for accurately predicting the outcomes of non-stand-replacing disturbance in intermediate-age forests. We quantified net ecosystem production (NEP), aboveground net primary production (ANPP), and the dynamics of major carbon (C) pools before and during the decade [...] Read more.
Understanding processes underlying forest carbon dynamics is essential for accurately predicting the outcomes of non-stand-replacing disturbance in intermediate-age forests. We quantified net ecosystem production (NEP), aboveground net primary production (ANPP), and the dynamics of major carbon (C) pools before and during the decade following invasive insect defoliation and prescribed fires in oak- and pine-dominated stands in the New Jersey Pinelands National Reserve, USA. Gross ecosystem production (GEP) recovered during the year following defoliation at the oak stand, but tree mortality increased standing dead and coarse woody debris, and ecosystem respiration (Re) accounted for >97% of GEP. As a result, NEP averaged only 22% of pre-disturbance values during the decade following defoliation. At the pine stand, GEP also recovered to pre-disturbance values during the year following understory defoliation by gypsy moth and two prescribed fires, while Re was nearly unaffected. Overall, defoliation and tree mortality at the oak stand drove a decadal-scale reduction in NEP that was twofold greater in magnitude than C losses associated with prescribed fires at the pine stand. Our study documents the outcomes of different non-stand-replacing disturbances, and highlights the importance of detrital dynamics and increased Re in long-term measurements of forest C dynamics following disturbance in intermediate-age forests. Full article
(This article belongs to the Special Issue Forest Structural Dynamics in the 21st Century)
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16 pages, 6652 KiB  
Article
Effects of Tree Trunks on Estimation of Clumping Index and LAI from HemiView and Terrestrial LiDAR
by Yunfei Bao, Wenjian Ni, Dianzhong Wang, Chunyu Yue, Hongyan He and Hans Verbeeck
Forests 2018, 9(3), 144; https://doi.org/10.3390/f9030144 - 16 Mar 2018
Cited by 21 | Viewed by 4744
Abstract
Estimating clumping indices is important for determining the leaf area index (LAI) of forest canopies. The spatial distribution of the clumping index is vital for LAI estimation. However, the neglect of woody tissue can result in biased clumping index estimates when indirectly deriving [...] Read more.
Estimating clumping indices is important for determining the leaf area index (LAI) of forest canopies. The spatial distribution of the clumping index is vital for LAI estimation. However, the neglect of woody tissue can result in biased clumping index estimates when indirectly deriving them from the gap probability and LAI observations. It is difficult to effectively and automatically extract woody tissue from digital hemispherical photos. In this study, a method for the automatic detection of trunks from Terrestrial Laser Scanning (TLS) data was used. Between-crown and within-crown gaps from TLS data were separated to calculate the clumping index. Subsequently, we analyzed the gap probability, clumping index, and LAI estimates based on TLS and HemiView data in consideration of woody tissue (trunks). Although the clumping index estimated from TLS had better agreement (R2 = 0.761) than that from HemiView, the change of angular distribution of the clumping index affected by the trunks from TLS data was more obvious than with the HemiView data. Finally, the exclusion of the trunks led to a reduction in the average LAI by ~19.6% and 8.9%, respectively, for the two methods. These results also showed that the detection of woody tissue was more helpful for the estimation of clumping index distribution. Moreover, the angular distribution of the clumping index is more important for the LAI estimate than the average clumping index value. We concluded that woody tissue should be detected for the clumping index estimate from TLS data, and 3D information could be used for estimating the angular distribution of the clumping index, which is essential for highly accurate LAI field measurements. Full article
(This article belongs to the Special Issue Remote Sensing of Leaf Area Index (LAI) and Other Vegetation Parameters)
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17 pages, 1320 KiB  
Article
Factors Affecting Natural Regeneration of Tropical Forests across a Precipitation Gradient in Myanmar
by Inkyin Khaine, Su Young Woo, MyeongJa Kwak, Seong Han Lee, Sun Mi Je, Hana You, Taeyoon Lee, Jihwi Jang, Hyun Kyung Lee, Hyo Cheng Cheng, Jeong Ho Park, Euddeum Lee, Yang Li, Haenaem Kim, Jong Kyu Lee and Jieun Kim
Forests 2018, 9(3), 143; https://doi.org/10.3390/f9030143 - 15 Mar 2018
Cited by 34 | Viewed by 10089
Abstract
Natural regeneration is an essential component of forest dynamics and the recovery of ecosystem functions. Therefore, understanding regeneration status, and how abiotic and biotic factors affect it, is important for ecological studies. This study discovered different regeneration statuses of tropical forests in response [...] Read more.
Natural regeneration is an essential component of forest dynamics and the recovery of ecosystem functions. Therefore, understanding regeneration status, and how abiotic and biotic factors affect it, is important for ecological studies. This study discovered different regeneration statuses of tropical forests in response to differences in rainfall in Myanmar, and the environmental and overstory factors that had the most influence on understory regeneration. Study sites were set up in regions with 625 to 2035 mm of annual rainfall, and ecological characteristics were measured. According to the results, natural regeneration increased with rainfall, showing a good regeneration status at all sites. Forests within a range of 1411–2035 mm of annual rainfall had a significantly higher density and species diversity at specific natural regeneration stages than those with 625–1029 mm. Not only abiotic but also overstory structure affected the natural regeneration of forests. However, not all factors influenced natural regeneration status. Overstory size distribution parameters did not show a significant influence on natural regeneration. Average annual rainfall (abiotic), as well as ecosystem complexity, density, species richness, and diversity (overstory), were found to be the most influential factors for the density and diversity of natural regeneration. The results of this study will support silviculture and the management of tropical forests. Full article
(This article belongs to the Section Forest Ecology and Management)
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17 pages, 3546 KiB  
Review
Progress and Challenges of Protecting North American Ash Trees from the Emerald Ash Borer Using Biological Control
by Jian J. Duan, Leah S. Bauer, Roy G. Van Driesche and Juli R. Gould
Forests 2018, 9(3), 142; https://doi.org/10.3390/f9030142 - 15 Mar 2018
Cited by 69 | Viewed by 9779
Abstract
After emerald ash borer (EAB), Agrilus planipennis Fairmaire, was discovered in the United States, a classical biological control program was initiated against this destructive pest of ash trees (Fraxinus spp.). This biocontrol program began in 2007 after federal regulatory agencies and the [...] Read more.
After emerald ash borer (EAB), Agrilus planipennis Fairmaire, was discovered in the United States, a classical biological control program was initiated against this destructive pest of ash trees (Fraxinus spp.). This biocontrol program began in 2007 after federal regulatory agencies and the state of Michigan approved release of three EAB parasitoid species from China: Tetrastichus planipennisi Yang (Eulophidae), Spathius agrili Yang (Braconidae), and Oobius agrili Zhang and Huang (Encyrtidae). A fourth EAB parasitoid, Spathius galinae Belokobylskij (Braconidae) from Russia, was approved for release in 2015. We review the rationale and ecological premises of the EAB biocontrol program, and then report on progress in North American ash recovery in southern Michigan, where the parasitoids were first released. We also identify challenges to conserving native Fraxinus using biocontrol in the aftermath of the EAB invasion, and provide suggestions for program improvements as EAB spreads throughout North America. We conclude that more work is needed to: (1) evaluate the establishment and impact of biocontrol agents in different climate zones; (2) determine the combined effect of EAB biocontrol and host plant resistance or tolerance on the regeneration of North American ash species; and (3) expand foreign exploration for EAB natural enemies throughout Asia. Full article
(This article belongs to the Special Issue Understanding and Managing Emerald Ash Borer Impacts on Ash Forests)
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21 pages, 3063 KiB  
Article
Forest Plantations’ Externalities: An Application of the Analytic Hierarchy Process to Non-Industrial Forest Owners in Central Chile
by Giorgia Bottaro, Lisandro Roco, Davide Pettenella, Stefano Micheletti and Julien Vanhulst
Forests 2018, 9(3), 141; https://doi.org/10.3390/f9030141 - 15 Mar 2018
Cited by 8 | Viewed by 5851
Abstract
The forestry sector in Chile has an important role in the domestic economy, being the second leading export sector after the mining industry. Investments in forest plantations have grown in the last 40 years thanks to implementation of the Decree Law 701. Planted [...] Read more.
The forestry sector in Chile has an important role in the domestic economy, being the second leading export sector after the mining industry. Investments in forest plantations have grown in the last 40 years thanks to implementation of the Decree Law 701. Planted forests currently account for 17.4% of the total national forest cover. The objective of the study is to analyse non-industrial forest owners’ perceptions of positive and negative externalities of forest plantations in four less developed municipalities of the Maule Region. We implemented a literature review, the estimation of an Expert’s Response Indicator (ERI), and the implementation of an Analytic Hierarchy Process (AHP) methodology for the analysis. The results indicate that non-industrial forest owners in the four municipalities perceive the importance of each externality in a different way according to their territorial specificities. However, considering the whole study area, “CO2 sequestration”, “improvement of livelihood”, and “more importance of small and medium forest owners” were considered the most important positive externalities, while the most relevant negative externalities were “water shortage”, “power asymmetry”, and “land loss”. The study encourages further research with a similar detailed analysis on stakeholders’ perceptions of plantation projects, both to revise investment features and inform local stakeholders on their real impacts. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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17 pages, 2592 KiB  
Article
Phenotypic and Genotypic Correlations for Wood Properties of Hybrid Poplar Clones of Southern Quebec
by A.S.M. Azmul Huda, Ahmed Koubaa, Alain Cloutier, Roger E. Hernández, Pierre Périnet and Yves Fortin
Forests 2018, 9(3), 140; https://doi.org/10.3390/f9030140 - 15 Mar 2018
Cited by 10 | Viewed by 4184
Abstract
This study aims to understand the phenotypic and genotypic correlations among wood anatomical, physical, and mechanical properties of hybrid poplar clones. Samples were taken from seven clones grown on three sites in Southern Quebec, Canada. Five trees per clone were randomly sampled from [...] Read more.
This study aims to understand the phenotypic and genotypic correlations among wood anatomical, physical, and mechanical properties of hybrid poplar clones. Samples were taken from seven clones grown on three sites in Southern Quebec, Canada. Five trees per clone were randomly sampled from each site to measure anatomical (fiber length, fiber proportion, vessel proportion, fiber wall thickness, tension wood), physical (basic density, volumetric, longitudinal, tangential, and radial shrinkage), and mechanical wood properties (flexural modulus of elasticity (MOE), modulus of rupture (MOR), ultimate crushing strength parallel to the grain). The observed phenotypic and genotypic correlations between these wood properties were moderate to strong, except for fiber length and vessel proportion. Genotypic correlations for all wood properties were higher than for corresponding phenotypic correlations. Furthermore, fiber length showed weak correlations, whereas, vessel proportion showed strongly negative correlations with all other properties. Strong correlations were also found among fiber proportion, fiber wall thickness, basic density, and mechanical properties. Furthermore, results from this study show close genotypic and phenotypic correlations between fiber proportion, fiber wall thickness, and wood density, which consequently affect the mechanical performance of wood products. These findings indicate that there is a substantial opportunity to improve wood quality by selecting several wood properties for different end uses. Full article
(This article belongs to the Special Issue Wood Property Responses to Silvicultural Treatments)
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17 pages, 3645 KiB  
Article
Treatment of Picea abies and Pinus sylvestris Stumps with Urea and Phlebiopsis gigantea for Control of Heterobasidion
by Kalle Kärhä, Ville Koivusalo, Teijo Palander and Matti Ronkanen
Forests 2018, 9(3), 139; https://doi.org/10.3390/f9030139 - 15 Mar 2018
Cited by 10 | Viewed by 5111
Abstract
Heterobasidion spp. root rot causes severe damage to forests throughout the northern temperate zone. In order to prevent Heterobasidion infection in summertime cuttings, stumps can be treated with urea or Phlebiopsis gigantea. In this study, the consumption of stump treatment materials and [...] Read more.
Heterobasidion spp. root rot causes severe damage to forests throughout the northern temperate zone. In order to prevent Heterobasidion infection in summertime cuttings, stumps can be treated with urea or Phlebiopsis gigantea. In this study, the consumption of stump treatment materials and the quality of stump treatment work were investigated. A total of 46 harvesters were examined in May–November 2016 in Finland. The average stem size of softwood removal and softwood removal per hectare explained the consumption of stump treatment material. The quality of stump treatment work was good in the study. The best coverage was achieved with the stumps of 20–39 cm diameter at stump height (d0). It can be recommended that the harvester operator self-monitors and actively controls his/her treatment result in cutting work and sets the stump treatment equipment in a harvester if needed. The results also suggested that when cutting mostly small- and medium-diameter (d0 ≤ 39 cm) conifers, the stump treatment guide bars with relatively few (<18) open holes are used, and at the harvesting sites of large-diameter trees, the guide bars with a relatively great (>27) number of open holes are applied. Full article
(This article belongs to the Special Issue Forest Operations, Engineering and Management)
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18 pages, 12136 KiB  
Article
Ten Years of Monitoring Illustrates a Cascade of Effects of White Pine Blister Rust and Focuses Whitebark Pine Restoration in the Canadian Rocky and Columbia Mountains
by Brenda Shepherd, Brad Jones, Robert Sissons, Jed Cochrane, Jane Park, Cyndi M. Smith and Natalie Stafl
Forests 2018, 9(3), 138; https://doi.org/10.3390/f9030138 - 14 Mar 2018
Cited by 21 | Viewed by 5940
Abstract
Whitebark pine forests are declining due to infection by white pine blister rust and mountain pine beetle, combined with the effects of climate change and fire suppression. The Canadian Rocky and Columbia Mountains represent a large portion of the whitebark range; a vast [...] Read more.
Whitebark pine forests are declining due to infection by white pine blister rust and mountain pine beetle, combined with the effects of climate change and fire suppression. The Canadian Rocky and Columbia Mountains represent a large portion of the whitebark range; a vast area, exemplifying the need for knowledge about whitebark pine stands to target restoration. The aim of our work was to identify variables predicting live tree infection, seedling infection, canopy kill, mortality, and regeneration across this region, and present the results in spatially-explicit formats to assist land managers with restoration. Live tree and seedling infection by white pine blister rust increased over the last decade and cascading effects of the disease are intensifying, including canopy kill and mortality. We show that large diameter trees are more likely to be infected, and the highest infection rates are in southern and western areas. The conditions for seedling infection are more strongly influenced by fine-scale climatic conditions than for trees. Areas with low regeneration are: (1) the dry east slopes where live tree infection is low; and (2) where live tree infection rates are high, suggesting that canopy kill and mortality are influencing regeneration. Results highlight where to target restoration and coordinate across boundaries. Full article
(This article belongs to the Special Issue Ecology and Restoration of Whitebark Pine)
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17 pages, 3543 KiB  
Article
Ecoregional Patterns of Spruce Budworm—Wildfire Interactions in Central Canada’s Forests
by Jean-Noël Candau, Richard A. Fleming and Xianli Wang
Forests 2018, 9(3), 137; https://doi.org/10.3390/f9030137 - 14 Mar 2018
Cited by 15 | Viewed by 5402
Abstract
Wildfires and outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), are the two dominant natural disturbances in Canada’s boreal forest. While both disturbances have specific impacts on forest ecosystems, it is increasingly recognized that their interactions also have the potential for non-linear behavior [...] Read more.
Wildfires and outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.), are the two dominant natural disturbances in Canada’s boreal forest. While both disturbances have specific impacts on forest ecosystems, it is increasingly recognized that their interactions also have the potential for non-linear behavior and long-lasting legacies on forest ecosystems’ structures and functions. Previously, we showed that, in central Canada, fires occurred with a disproportionately higher frequency during a ‘window of opportunity’ following spruce budworm defoliation. In this study, we use Ontario’s spatial databases for large fires and spruce budworm defoliation to locate where these two disturbances likely interacted. Classification tree and Random Forest procedures were then applied to find how spruce budworm defoliation history, climate, and forest conditions best predict the location of such budworm–fire interactions. Results indicate that such interactions likely occurred in areas geographically bound by hardwood content in the south, the prevalence of the three major spruce budworm host species (balsam fir, white spruce and black spruce) in the north, and climate moisture in the west. The occurrence of a spruce budworm–fire interaction inside these boundaries is related to the frequency of spruce budworm defoliation. These patterns provide a means of distinguishing regions where spruce budworm attacks are likely to increase fire risk. Full article
(This article belongs to the Special Issue Wildland Fire, Forest Dynamics, and Their Interactions)
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20 pages, 1622 KiB  
Article
Role of Community and User Attributes in Collective Action: Case Study of Community-Based Forest Management in Nepal
by Swati Negi, Thu Thuy Pham, Bhaskar Karky and Claude Garcia
Forests 2018, 9(3), 136; https://doi.org/10.3390/f9030136 - 13 Mar 2018
Cited by 20 | Viewed by 5252
Abstract
A growing literature on collective action focuses on exploring the conditions that might help or hinder groups to work collectively. In this paper, we focus on community-based forest management in the inner Terai region of Nepal and explore the role of community and [...] Read more.
A growing literature on collective action focuses on exploring the conditions that might help or hinder groups to work collectively. In this paper, we focus on community-based forest management in the inner Terai region of Nepal and explore the role of community and user attributes such as group size, social heterogeneities, forest user’ perception on forests, and affiliation to the user group, in the collective action of managing community forests. Household surveys were carried out with 180 households across twelve community forest users’ groups. We first measured ethnic diversity, income inequality, landholding inequality, and user perception towards the use and management of community forests to understand their effect on the participation of forest users in the management of community forests. Our results show that among the studied variables, group size (number of forest users affiliated to the community forests) and perception of the management of their community forests are strong predictors of forest user participation in community forest management. Income inequality and ethnic diversity were found to have no significant association. Land inequality, however, was found to decrease participation in the management and use of community forests. These community and user attributes play a crucial role in the success of collective action and may vary from community to community. Hence they need to be duly considered by the practitioners prior to any community-based project interventions for stimulating successful collective action. Full article
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19 pages, 10940 KiB  
Article
Relationships between Tree Age and Climate Sensitivity of Radial Growth in Different Drought Conditions of Qilian Mountains, Northwestern China
by Lingnan Zhang, Yuan Jiang, Shoudong Zhao, Liang Jiao and Yan Wen
Forests 2018, 9(3), 135; https://doi.org/10.3390/f9030135 - 12 Mar 2018
Cited by 30 | Viewed by 4424
Abstract
The response of radial growth to climate and the climate sensitivity of tree growth at different ages in different drought conditions are essential for predicting forest dynamics and making correct forest management policies. In this study, we analyzed the growth responsiveness of Picea [...] Read more.
The response of radial growth to climate and the climate sensitivity of tree growth at different ages in different drought conditions are essential for predicting forest dynamics and making correct forest management policies. In this study, we analyzed the growth responsiveness of Picea crassifolia Kom. to climate and explored the relationship between age and climate sensitivity of radial growth at the individual tree scale in the wetter eastern area and drier western area of the Qilian Mountains. Pearson correlation coefficients were calculated between the chronology of each tree and climatic factors to examine the climate-growth relationships. Linear fitting, quadratic polynomial fitting and exponential fitting were used to test the relationships between age and mean sensitivity, standard deviation and radial growth’s response to climate. Trees in the wetter eastern area showed a weaker response to climate than those in the drier western area and were significantly correlated with precipitation and mean temperature in the previous and current mid-late summer. Trees in the drier western area were mainly limited by precipitation of the previous August, the current May and June, as well as limited by temperature in the previous and current early-middle summer. In the wetter area, the younger trees were more sensitive to both precipitation and temperature than the older trees. In the drier area, younger/older trees showed a stronger sensitivity to precipitation in the current August and September/May, whereas trees 120–140 years old showed a stronger correlation with temperature factors in the summer. It was determined that mature trees in the drier area were more strongly influenced by the climate, especially in the context of increasing temperature. These trees should be paid special attention in forest management. Full article
(This article belongs to the Special Issue Interactions Matter — Complex Effects of Competition, Disturbances, and Climate on Tree Growth)
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18 pages, 2831 KiB  
Article
High-Resolution Analytical Approach to Describe the Sensitivity of Tree–Environment Dependences through Stem Radial Variation
by Claudia Cocozza, Roberto Tognetti and Alessio Giovannelli
Forests 2018, 9(3), 134; https://doi.org/10.3390/f9030134 - 12 Mar 2018
Cited by 14 | Viewed by 4325
Abstract
Stem radius variations are remarkably synchronous to weather conditions. Climate fluctuations can forecast the occurrence and severity of environmental disturbance on radial variations, as well as tissue sensitivity and tree growth. Radial variations were detected through dendrometers and were analyzed coupled to environmental [...] Read more.
Stem radius variations are remarkably synchronous to weather conditions. Climate fluctuations can forecast the occurrence and severity of environmental disturbance on radial variations, as well as tissue sensitivity and tree growth. Radial variations were detected through dendrometers and were analyzed coupled to environmental conditions to define stem sensitivity in response to experimental (logs in lab) and natural (trees in field) drivers. By using a mathematical approach for the analysis of plant traits and environmental variables, this study aimed at highlighting a methodological framework to analytically unravel the environmental control of stem cycles. A derivative analysis was performed on data derived from experimental measurements, which showed a high degree of agreement between environmental drivers and dendrometer signals. The analytical approach provided information on plant performance in response to environmental variation, removing the confounding effects of different variables. Coding of the dendrometer signal provided a process to quantify stem sensitivity to ambient temperature, to portray synchronicity of time series related to stem radial variations and air temperature events, and to identify time lags of environmental effects on plant traits. Full article
(This article belongs to the Special Issue Tree Ecophysiology: Responses and Adaptation to a Changing Environment)
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22 pages, 767 KiB  
Review
The Interplay between Forest Management Practices, Genetic Monitoring, and Other Long-Term Monitoring Systems
by Darius Kavaliauskas, Barbara Fussi, Marjana Westergren, Filippos Aravanopoulos, Domen Finzgar, Roland Baier, Paraskevi Alizoti, Gregor Bozic, Evangelia Avramidou, Monika Konnert and Hojka Kraigher
Forests 2018, 9(3), 133; https://doi.org/10.3390/f9030133 - 10 Mar 2018
Cited by 19 | Viewed by 5467
Abstract
The conservation and sustainable use of forests and forest genetic resources (FGR) is a challenging task for scientists and foresters. Forest management practices can affect diversity on various levels: genetic, species, and ecosystem. Understanding past natural disturbance dynamics and their level of dependence [...] Read more.
The conservation and sustainable use of forests and forest genetic resources (FGR) is a challenging task for scientists and foresters. Forest management practices can affect diversity on various levels: genetic, species, and ecosystem. Understanding past natural disturbance dynamics and their level of dependence on human disturbances and management practices is essential for the conservation and management of FGR, especially in the light of climate change. In this review, forest management practices and their impact on genetic composition are reviewed, synthesized, and interpreted in the light of existing national and international forest monitoring schemes and concepts from various European projects. There is a clear need and mandate for forest genetic monitoring (FGM), while the requirements thereof lack complementarity with existing forest monitoring. Due to certain obstacles (e.g., the lack of unified FGM implementation procedures across the countries, high implementation costs, large number of indicators and verifiers for FGM proposed in the past), merging FGM with existing forest monitoring is complicated. Nevertheless, FGM is of paramount importance for forestry and the natural environment in the future, regardless of the presence or existence of other monitoring systems, as it provides information no other monitoring system can yield. FGM can provide information related to adaptive and neutral genetic diversity changes over time, on a species and/or on a population basis and can serve as an early warning system for the detection of potentially harmful changes of forest adaptability. In addition, FGM offers knowledge on the adaptive potential of forests under the changing environment, which is important for the long-term conservation of FGR. Full article
(This article belongs to the Special Issue Forest Policy and Biodiversity Strategy: The Relevance of Forest Genetic Resources)
13 pages, 2239 KiB  
Article
Comparison of the Economic Value of Urban Trees through Surveys with Photographs in Two Seasons
by Claudia García-Ventura, Álvaro Sánchez-Medina, M. Ángeles Grande-Ortíz, Concepción González-García and Esperanza Ayuga-Téllez
Forests 2018, 9(3), 132; https://doi.org/10.3390/f9030132 - 10 Mar 2018
Cited by 2 | Viewed by 4420
Abstract
Urban trees are generally considered to be a public asset and are an important part of a city’s heritage. The aim of this work is to analyse the influence of season on the economic appraisal of various trees in Madrid. Photographs were taken [...] Read more.
Urban trees are generally considered to be a public asset and are an important part of a city’s heritage. The aim of this work is to analyse the influence of season on the economic appraisal of various trees in Madrid. Photographs were taken of 43 individual tree specimens in summer and winter. The survey was designed to compare differences of opinion in the economic assessment of trees. The trees were assessed by eight valuation methods used worldwide. A total of 78 agroforestry engineering students answered a written survey, and the variables considered were: percentage of students who always evaluated the tree equally (%0), percentage of students who assigned more value to the summer photograph (%S), and percentage of students who assigned more value to the winter photograph (%W). The results were analysed by the statistical test of equal proportions and ANOVA to detect differences according to tree type (evergreen or deciduous), species, and other groupings made by the authors in previous works. W and S percentages are similar. The ANOVA analysis rejects the equality of percentages of S and W between groups. The Welch test rejects the equality of the percentage of S, W, and O between species. Full article
(This article belongs to the Special Issue Participatory Forestry: Involvement, Information and Science)
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16 pages, 2820 KiB  
Article
Pinus albicaulis Engelm. (Whitebark Pine) in Mixed-Species Stands throughout Its US Range: Broad-Scale Indicators of Extent and Recent Decline
by Sara A. Goeking and Deborah Kay Izlar
Forests 2018, 9(3), 131; https://doi.org/10.3390/f9030131 - 9 Mar 2018
Cited by 27 | Viewed by 6787
Abstract
We used data collected from >1400 plots by a national forest inventory to quantify population-level indicators for a tree species of concern. Whitebark pine (Pinus albicaulis) has recently experienced high mortality throughout its US range, where we assessed the area of [...] Read more.
We used data collected from >1400 plots by a national forest inventory to quantify population-level indicators for a tree species of concern. Whitebark pine (Pinus albicaulis) has recently experienced high mortality throughout its US range, where we assessed the area of land with whitebark pine present, size-class distribution of individual whitebark pine, growth rates, and mortality rates, all with respect to dominant forest type. As of 2016, 51% of all standing whitebark pine trees in the US were dead. Dead whitebark pines outnumbered live ones—and whitebark pine mortality outpaced growth—in all size classes ≥22.8 cm diameter at breast height (DBH), across all forest types. Although whitebark pine occurred across 4.1 million ha in the US, the vast majority of this area (85%) and of the total number of whitebark pine seedlings (72%) fell within forest types other than the whitebark pine type. Standardized growth of whitebark pines was most strongly correlated with the relative basal area of whitebark pine trees (rho = 0.67; p < 0.01), while both standardized growth and mortality were moderately correlated with relative whitebark pine stem density (rho = 0.39 and 0.40; p = 0.031 and p < 0.01, respectively). Neither growth nor mortality were well correlated with total stand basal area, total stem density, or stand mean diameter. The abundance, extent, and relative growth vs. mortality rates of whitebark pine in multiple forest types presents opportunities for management to encourage whitebark pine recruitment in mixed-species stands. The lodgepole pine forest type contained more whitebark pine seedlings (35%) than any other forest type, suggesting that this forest type represents a potential management target for silvicultural treatments that seek to facilitate the recruitment of whitebark pine seedlings into larger size classes. National forest inventories in other countries may use a similar approach to assess species of concern. Full article
(This article belongs to the Special Issue Ecology and Restoration of Whitebark Pine)
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26 pages, 5604 KiB  
Article
Predicting Potential Fire Severity Using Vegetation, Topography and Surface Moisture Availability in a Eurasian Boreal Forest Landscape
by Lei Fang, Jian Yang, Megan White and Zhihua Liu
Forests 2018, 9(3), 130; https://doi.org/10.3390/f9030130 - 8 Mar 2018
Cited by 48 | Viewed by 7410
Abstract
Severity of wildfires is a critical component of the fire regime and plays an important role in determining forest ecosystem response to fire disturbance. Predicting spatial distribution of potential fire severity can be valuable in guiding fire and fuel management planning. Spatial controls [...] Read more.
Severity of wildfires is a critical component of the fire regime and plays an important role in determining forest ecosystem response to fire disturbance. Predicting spatial distribution of potential fire severity can be valuable in guiding fire and fuel management planning. Spatial controls on fire severity patterns have attracted growing interest, but few studies have attempted to predict potential fire severity in fire-prone Eurasian boreal forests. Furthermore, the influences of fire weather variation on spatial heterogeneity of fire severity remain poorly understood at fine scales. We assessed the relative importance and influence of pre-fire vegetation, topography, and surface moisture availability (SMA) on fire severity in 21 lightning-ignited fires occurring in two different fire years (3 fires in 2000, 18 fires in 2010) of the Great Xing’an Mountains with an ensemble modeling approach of boosted regression tree (BRT). SMA was derived from 8-day moderate resolution imaging spectroradiometer (MODIS) evapotranspiration products. We predicted the potential distribution of fire severity in two fire years and evaluated the prediction accuracies. BRT modeling revealed that vegetation, topography, and SMA explained more than 70% of variations in fire severity (mean 83.0% for 2000, mean 73.8% for 2010). Our analysis showed that evergreen coniferous forests were more likely to experience higher severity fires than the dominant deciduous larch forests of this region, and deciduous broadleaf forests and shrublands usually burned at a significantly lower fire severity. High-severity fires tended to occur in gentle and well-drained slopes at high altitudes, especially those with north-facing aspects. SMA exhibited notable and consistent negative association with severity. Predicted fire severity from our model exhibited strong agreement with the observed fire severity (mean r2 = 0.795 for 2000, 0.618 for 2010). Our results verified that spatial variation of fire severity within a burned patch is predictable at the landscape scale, and the prediction of potential fire severity could be improved by incorporating remotely sensed biophysical variables related to weather conditions. Full article
(This article belongs to the Special Issue Wildland Fire, Forest Dynamics, and Their Interactions)
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17 pages, 1228 KiB  
Article
Institutional and Actor-Oriented Factors Constraining Expert-Based Forest Information Exchange in Europe: A Policy Analysis from an Actor-Centred Institutionalist Approach
by Tanya Baycheva-Merger, Metodi Sotirov, Sara Holmgren and Andy Selter
Forests 2018, 9(3), 129; https://doi.org/10.3390/f9030129 - 8 Mar 2018
Cited by 14 | Viewed by 7295
Abstract
Adequate and accessible expert-based forest information has become increasingly in demand for effective decisions and informed policies in the forest and forest-related sectors in Europe. Such accessibility requires a collaborative environment and constant information exchange between various actors at different levels and across [...] Read more.
Adequate and accessible expert-based forest information has become increasingly in demand for effective decisions and informed policies in the forest and forest-related sectors in Europe. Such accessibility requires a collaborative environment and constant information exchange between various actors at different levels and across sectors. However, information exchange in complex policy environments is challenging, and is often constrained by various institutional, actor-oriented, and technical factors. In forest policy research, no study has yet attempted to simultaneously account for these multiple factors influencing expert-based forest information exchange. By employing a policy analysis from an actor-centred institutionalist perspective, this paper aims to provide an overview of the most salient institutional and actor-oriented factors that are perceived as constraining forest information exchange at the national level across European countries. We employ an exploratory research approach, and utilise both qualitative and quantitative methods to analyse our data. The data was collected through a semi-structured survey targeted at forest and forest-related composite actors in 21 European countries. The results revealed that expert-based forest information exchange is constrained by a number of compound and closely interlinked institutional and actor-oriented factors, reflecting the complex interplay of institutions and actors at the national level. The most salient institutional factors that stand out include restrictive or ambiguous data protection policies, inter-organisational information arrangements, different organisational cultures, and a lack of incentives. Forest information exchange becomes even more complex when actors are confronted with actor-oriented factors such as issues of distrust, diverging preferences and perceptions, intellectual property rights, and technical capabilities. We conclude that expert-based forest information exchange is a complex and challenging task. It is driven by actors’ preferences/interests, perceptions, and capabilities, and is shaped by formal rules and social norms. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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15 pages, 1132 KiB  
Article
Root Infection of Canker Pathogens, Fusarium circinatum and Diplodia sapinea, in Asymptomatic Trees in Pinus radiata and Pinus pinaster Plantations
by Laura Hernandez-Escribano, Eugenia Iturritxa, Ana Aragonés, Nebai Mesanza, Mónica Berbegal, Rosa Raposo and Margarita Elvira-Recuenco
Forests 2018, 9(3), 128; https://doi.org/10.3390/f9030128 - 8 Mar 2018
Cited by 16 | Viewed by 5196
Abstract
The existence of a latent stage within host tissue of the pine pathogens Fusarium circinatum and Diplodia sapinea, the causal agents of pitch canker and shoot blight disease respectively, has previously been cited. However, studies on this cryptic phase in each disease lifecycle [...] Read more.
The existence of a latent stage within host tissue of the pine pathogens Fusarium circinatum and Diplodia sapinea, the causal agents of pitch canker and shoot blight disease respectively, has previously been cited. However, studies on this cryptic phase in each disease lifecycle has only been focused on the host aerial parts but not on the roots. Therefore, our objective was to analyze the presence of both pathogens in roots of non-symptomatic mature trees in plantations where the pathogens are known to be causing canker symptoms. For that, we sampled roots from ten non-symptomatic and ten symptomatic trees in three Pinus radiata and one Pinus pinaster plantations in Basque Country, Spain. Both pathogens were isolated from roots of non-symptomatic trees in a higher frequency than from roots of symptomatic trees, 23.3% and 6.6% respectively for D. sapinea and 16.6% and 3.3% respectively for F. circinatum. Neither pathogens was detected in the P. pinaster plantation. The two pathogens were never isolated from the same tree. A high molecular variability was observed for D. sapinea isolates with six different haplotypes and two mating types for the eleven characterized isolates, but only one haplotype and mating type was found for F. circinatum, with all isolates of both fungi being proved pathogenic. These results evidence the importance root infection may have in the disease lifecycle and, therefore, disease management. Full article
(This article belongs to the Special Issue Pine Pitch Canker—Strategies for Management of Gibberella Circinata in Greenhouses and Forests (PINESTRENGTH))
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20 pages, 2303 KiB  
Article
Allocation of Storage Yards in Management Plans in the Amazon by Means of Mathematical Programming
by Evandro Ferreira da Silva, Gilson Fernandes Da Silva, Evandro Orfanó Figueiredo, Daniel Henrique Breda Binoti, Adriano Ribeiro de Mendonça, Carlos Moreira Miquelino Eleto Torres and José Eduardo Macedo Pezzopane
Forests 2018, 9(3), 127; https://doi.org/10.3390/f9030127 - 8 Mar 2018
Cited by 8 | Viewed by 5287
Abstract
The present study aimed to optimize the location of wood storage yards in forest management for the production of wood in the Brazilian Amazon. The area of forest management studied was 638.17 ha, with 1478 trees selected for harvest with a diameter at [...] Read more.
The present study aimed to optimize the location of wood storage yards in forest management for the production of wood in the Brazilian Amazon. The area of forest management studied was 638.17 ha, with 1478 trees selected for harvest with a diameter at breast height of at least 50 cm in accordance with Brazilian legislation. Taking the topography into account—permanent preservation areas, restricted areas, and remaining trees—and using GIS tools, 7896 sites were identified that could be used as wood storage yards. By using mathematical programming techniques, more specifically binary integer linear programming, and based on the classical p-median model, optimal locations for the opening of yards were defined. Four scenarios were proposed combining distance and volume constraints. The scenarios evaluated promoted reductions in infrastructure investment compared with traditional planning. The results showed reductions in the number of forest roads (–6.33%) and trails to extract logs (–15.49%) when compared to traditional planning. The best performing scenario was that with the maximum volume restriction. It was concluded that the application of mathematical programming was able to promote significant gains in the harvest planning of native forests of the Amazon with the potential to reduce environmental damage. Full article
(This article belongs to the Special Issue Decision Support Approaches in Adaptive Forest Management—Selected Papers from the IUFRO 125th Anniversary Congress)
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