Biomass Dynamics in a Fragment of Brazilian Tropical Forest (Caatinga) over Consecutive Dry Years

Round 1

Reviewer 1 Report

I think the work can be accepted by showing interest in explaining how the succession in a tropical dry forest within the example of the Caatinga.

I have some comments ordered by lines:

Line 34: Include a reference after ‘surface’

Line 42: Include a reference after ‘region’

Line 63: ‘aoocurred? What does this mean?

Line 95 and others: Species names should be written in italics followed by their author only the first time they are written.

Line 102: Why are 10 x 10 m plots used? Do these measures cover a greater diversity? Please explain what the criteria was.

Line 118: Please, add a reference after Meteorological Database for Teaching and Research (BDMEP/INMET).

Line 134 and 135: Why do you use these tests? Please, explain it in a sentence.

Line 160: In this table, we can see T and R, but where is ETP?

References: Please, see the publication rules for the bibliography. References do not follow MDPI templates. Information on-line is only indicated when it is a web page. In addition, the doi of the magazine must be added. But there are also other errors, for example:

In 2 the name of the journal is incorrectly written; in 4, the publisher is missing; the names of all authors must be written; In 7, change Natura to Nature; in 8, change Cheilantha to cheilantha; in 11, change ‘área’ to ‘area’, etc, etc.

Figure 6: Please, change the color of ‘climate normal rainfall’ because it can be confused with ‘water availability’. The same for figure 7.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript provides interesting information on the influence of consecutive years of drought, due to climate change, on tree mortality and recruitment in a tropical dry forest (Catinga) in Brazil. Most of the manuscript is easy to follow by the reader, however, the Results-Discussion section needs major improvements for a better understanding of the study findings. English should be also improved.

 

Some suggestions are provided below.

 

L34. Define “dryland”. Provide some numbers (e.g. water deficit, climate, weather, etc.).

L36. Tropical dry forests (TDFs) are how usually is reported in the literature.

L41. Replace “inserted” by located.

L46. Does “small” mean a few species or short trees or shrubs? Please clarify this. Define “strong growth”.

L47. As a suggestion, replace “at the start” for “during the early processes of succession”.

L47. Define “more tolerant species”. Do you mean to “drought”?

L50. Define “variability”.

L54. “to recover”, do you mean to grow as expected?

L57. “the death of some trees may occur”, do you mean the probability of tree mortality increases?

L60. “However, little is known about the behavior of plant mortality in different dry forests in the face of climate change, partly due to the lack of long-term data.”

As a suggestion, this sentence could be like “However, lacking long-term data on droughts caused by climate change limits the understanding on tree mortality patterns in TDFs.”

L62. “losses” replace this for mortality.

L62. Wrong bracket “[12}”

L62-67. “The longest sequence of dry years to have aoocurred in the Brazilian semi-arid region (2010-2019), with a consequent reduction in water availability [17], raises the following question: How has this sequence of dry years affected the dynamics of biomass production in a Dry Tropical Forest in the Caatinga Phytogeographic Domain (DTF/CPD)? To answer this question, we hypothesise that there are 66 species in the study region that are resilient to consecutive years of severe drought.”

 

As a suggestion, this could be like “From 2010-2019, the Brazilian semi-arid region experienced the longest period of drought reported, and little is known about the biomass dynamics due to a reduction in water availability during this period. Based on this, this study assessed the biomass generated from this period by different species of plants in a Dry Tropical Forest in the Caatinga Phytogeographic Domain (DTF/CPD). Also, we determine the resilience of some species to this dry period.”

 

You should clearly define what do you mean by resilience here. Does resilience mean that trees of some species grow and “produced” biomass? Or Does resilience mean that trees for those species suffer less (or none) mortality during droughts?

From the information provided in the Introduction before this paragraph, it is hard to come up with a hypothesis. But the study can have a goal or an objective instead as suggested above.

The authors should define clearly in the Introduction was is considered “a dry year” by providing numbers about rainfall, water deficit, etc.

 

L68-71. This is a long-single-hard-to-follow-sentence-paragraph that should be written in two sentences at least.

L93. Provide some numbers to the “highly variable” statement.

L95. Corn farms instead of “maize”.

L104. Were instead of “was”.

L117. Was instead “were”.

L121. Five instead of “5”.

L125. “Not taking into account” instead of “ignoring”.

L133. “The normality of the data for the above-ground woody biomass was analysed using the 133 Shapiro-Wilk test (p≤0.05). Since a non-normal distribution was found, the” not needed.

L141. “Showed” instead “formed”.

L147. The Table referred here should have values for each year instead of a mean/cluster group. You can add the mean and SD for each cluster group as an extra column.

L161. Indicate the spells on the Table foot legend and mention what the values mean for each spell in the first paragraph of the Results. I guess it means the number of days/spell (C), but this is not clear.

L164. “identified in total”.

L165. Not clear what “crystalline” means.

L165-167. “Research 165 carried out in fragments of dry tropical forests (DTF/CPD) in the northeast of Brazil found values 166 that ranged from 6 to 26 families and from 12 to 64 species [25].”

 

Better: “The number of families ranged from 6 to 26, while species  from 12 to 64 [25].”

L168-169. Species should be in italics.

L172-176. You should provide the number of plants/ha from your study so the reader can compare right away to Araujo instead of going to the Table to find this number.

L185. Abundant instead of “profuse”.

L187-195. Species and genera should be in italics here and THROUGHOUT THE MS.

L201. Remove “relative to the period from”.

L210. Suggested: “Individuals that died during the study period had a wood density that was higher than the average for the area (0.660 g cm-3) (Table 2), suggesting that species with higher density, have less capacity to resist periods of prolonged drought.”

 

L217. Suggested: “Furthermore, when climate conditions exceed the plant tolerance limits (e.g. an increase in temperature and vapour pressure) [7], hydraulic failure can result in tree mortality due to [26] xylem embolism [29, 15]. Another factor possibly causing mortality is an excess of water in soils that affects water potential in both soils and plants [30].”

 

L222-234. This is good and interesting information but should be summarized and English reviewed.

L242. Not clear the meaning of “exploits”.

L242-244. This paragraph is not completely clear. Rewrite it and review the English.

L244. Replace “death” with the proper forestry term “mortality” THROUGHOUT THE MANUSCRIPT.

L246. “probably related to the age”, do you mean older trees suffer higher mortality???

L249. According to the Y-axis, Figure 5 legend is not a rate but a ratio or a proportion.

L268-270. “One of the strategies of forest communities to live with water stress is to reduce the number of trees, increasing the probability of survival of the remainder [7].”

This is sentences not clear at all…

So, the community seems to feel the water limitation and reduces the number of trees itself by selecting which ones survive and which ones won’t????

Please re-write it.

L270-271. “Such a strategy allows the water transport subsystems to re-establish themselves by reducing competition after the stress has eased [14].”

This should be re-written too.

The community does not have any strategy, it just happens. If a tree cannot have enough water and it is not adapted to cope with water scarcity dies, period.

I guess is the way is written so I suggest to re-write it and check the English.

 

L272-292. This is interesting and proper information regarding the results and Discussion, and even though I can understand what the authors mean, the information should be summarized and re-written.

I am not familiar with the Journal sections, but since this manuscript has the Results and Discussion together, the information shown should be written very concisely, basically explaining the findings in a very straightforward clear way. English should be checked.

 

L299-318. The same comment right above.

 

L325-326. Avoid a single-sentence paragraph.

L330. Not clear what “break” means.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors did a considerable effort in improving the manuscript. The new version highly improved the Results-Discussion section and I have no more comments or suggestions.

Author Response

Thank you very much for yours valuable comments and suggestions.