Sap Flow Density of the Prevailing Tree Species in a Hemiboreal Forest under Contrasting Meteorological and Growing Conditions
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe study addresses an important topic concerning the adaptive capacity of tree species to climate change (i.e. drought perturbance), specifically focusing on sap flow intensity in hemiboreal forests. The research is timely and relevant, given the increasing global concern over forest health and climate change. Though the study seems well-conducted and spans a relatively long period (two relatively wet years and two dry years), while I found the manuscript overall is not well-prepared and written, I think it could greatly benefit from language editing. I will only provide some suggestions on figures and tables for consideration.
1. Consider testing the differences among the four years in fig3.
2. Table3, give n for each species.
3. I do not find the information in Table 4 helpful, maybe consider plotting the meteorological parameters (as a time series), and highlighting the drought period with a 'gray box' or so.
4. 'sap flow intensity' is a quite unconventional term, just use sap flow density instead.
5. again, consider statistically testing the differences in Qs in Fig4
6. Fig5 is hard to understand
7. Fig6, see my comment for fig4
8. Fig7, consider a correlation heatmap plot
Comments on the Quality of English Language
I believe the manuscript could greatly benefit from language editing
Author Response
Rev.: I think it could greatly benefit from language editing. I will only provide some suggestions on figures and tables for consideration.
AA: English language editing is done.
- Consider testing the differences among the four years in fig3.
AA: standard error very simple index indicated the significance of the mean values of the considered parameters among objects. Based on it, it is very visible that 2017 and 2019 are the years which differed significantly from the rest monitored years.
- Table3, give n for each species.
AA: It is done.
- I do not find the information in Table 4 helpful, maybe consider plotting the meteorological parameters (as a time series), and highlighting the drought period with a 'gray box' or so.
AA: we tried to highlight the drought period
- 'sap flow intensity' is a quite unconventional term, just use sap flow density instead.
AA: It is done.
- again, consider statistically testing the differences in Qs in Fig4
AA: No additional information applying the different testes would be done… Sap flow density among the trees of one species differ not very significant while among the species – significantly.
- Fig5 is hard to understand
AA: it is explained
- Fig6, see my comment for fig4
- Standard of error is the simplest method which demonstrated significance in difference of the considered parameters. If the errors do not overwrought – the mean values differs significantly.
- Fig7, consider a correlation heatmap plot
AA: It could be done, but to our mind this data presentation method is more visible than heatmap plot method. It is evident which parameters inhibited sap flow density and which stimulated. No additional information on the relationships would be obtained applying the correlation heatmap plot method.
Comments on the Quality of English Language
I believe the manuscript could greatly benefit from language editing
AA: we have done it. The certificate is attached.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors looked at the responses of dominant tree species - Scots pine, Norway spruce, and silver birch - to the drought event in Lithuania. They looked at responses collected from two sites with different soils and contrasting water regimes - with water-limited and water-saturated
soils. The study looks balanced and ready for publication after minor corrections.
It would be beneficial for the research to pay more attention to the difference between the pine and spruce responses at the different temperature, VPD, and water regimes.
In the normal conditions the spruce shows better light use efficiency, hence, concurrency then the pine does. However, authors suggested the good drought adaptive mechanisms in spruce, and it does look that pine is better off during drought events.
Kind regards,
Author Response
In the normal conditions the spruce shows better light use efficiency, hence, concurrency then the pine does. However, authors suggested the good drought adaptive mechanisms in spruce, and it does look that pine is better off during drought events.
AA: we wanted to only highlight that spruce during the unfavorable period (drought) can close the stomata and in this way protects a tree from the water losses, while after the event the light rain fall immediately regenerates sapflow density. To our mind it is a sign of the good adaptive capacity to drought, because the increment even in the dry year exceeded the increment of the rest prevailing tree species in hemi-boreal forest.
Reviewer 3 Report
Comments and Suggestions for AuthorsEvaluation of the manuscript forests-3044706-peer-review-v1
SAP FLOW INTENSITY RATE OF THE PREVAILING TREE SPECIES IN HEMIBOREAL FOREST UNDER CONTRASTING METEOROLOGICAL AND GROWING CONDITION.
Algirdas Augustaitis * and Ainis Pivoras (†)
Agriculture Academy, Faculty of Forest Sciences and Ecology, Vytautas Magnus University, Studentų 13, Akademija, 53362 Kaunas, Lithuania
*Correspondence: [email protected]
General assessment of the research carried out and the results obtained
I appreciate the theme addressed in this scientific work, given that at this stage scientific research is facing unprecedented environmental challenges, where the conservation of agricultural biodiversity in general and the planet's forests in particular has become a vital weapon in the fight against climate change and in maintaining the ecological balance. Conservation of the forest ecosystem is of great importance, as forests are known to act as an essential carbon sink, absorbing carbon dioxide (CO2) from the atmosphere during the process of photosynthesis. This natural process allows trees to sequester substantial amounts of carbon in their biomass, roots and soils. According to the Food and Agriculture Organization (FAO), forests currently store more than 650 gigatons of carbon worldwide. When forests are destroyed or degraded, this carbon is released back into the atmosphere, exacerbating the greenhouse effect and contributing to global warming. Therefore, forest conservation not only helps prevent the release of stored carbon, but also offers a promising strategy for conserving biodiversity, stabilizing the hydrological cycle, and mitigating climate change through afforestation and reforestation efforts. The idea underlying the research in this material started from the possibility of preserving Lithuanian forests, consisting of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst) and silver birch (Betula pendula L.) under the conditions of the current climate changes taking place in Europe and around the globe, by assessing their capacity to adapt to different hydrological and fertility regimes. The aim of the researches was the adaptation capacity of the 3 dominant tree species in Lithuania to the integrated effects of environmental factors by studying the influence of meteorological factors and growing conditions on ecophysiological reactions.
I believe that this work was scientifically well documented, having a number of 53 bibliographic titles of which, 26% represent scientific news from the last 5 years, and 58% represent research results from the last 10 years. Self-citations do not represent a very large percentage, they are relevant for the study carried out, representing about 8% of the total number.
Scientific novelty
The study on the ecophysiological reactions of some forest species (scots pine, Norway spruce and silver birch) to contrasting meteorological events in different forest sites, can highlight their importance for Lithuanian forestry in the conditions of climate change with a tendency towards desertification. The scientific novelty consists in knowing the particularities of tree transpiration in extreme weather conditions, which is essential for the development of sustainable forest management strategies aimed at mitigating the negative effects of climate change. Through this research, the authors aim to contribute to the achievement of the Sustainable Development Goals of the United Nations for maintaining the hydrological and ecological balance of forests.
Observations on materials and methods
The work methodology is well presented, the authors clearly highlighting the location of the experiment, the quality of the forest biological material used, as well as the study conditions in two forest sites with different hydrological and fertility regimes. Aukštaitija IM station (AIMS) meteorological parameters and tree sap flow intensity are presented in detail to estimate forest transpiration under different conditions, both at the individual tree scale and at the stand scale. Also, experimental determinations and statistical analysis methods are relevant to the objectives of the study. Applying the Pearson linear correlation, relationships were established between the individual physiological parameters of the three forest species (scots pine, spruce and silver birch) and meteorological factors at different times: at the beginning of the growing season, before the drought, during the drought and after the drought.
Observations!
1) In the text, the author from no. 13, respectively:
Burgess S.; Downey A. SFM1 Sap Flow Meter Manual. 2014. Version 4.0. University Of Western Australia. ICT International Pty Ltd
2) Checking in-text reference citations was cumbersome. The journal's guidelines were not followed, according to which references should be numbered in order of appearance in the text and listed individually at the end of the manuscript, and in the text, reference numbers should be placed in square brackets [ ].
Thank you!
REVIEWER
Date: June 11, 2024
Comments for author File: 
Comments.pdf
Author Response
Observations!
1) In the text, the author from no. 13, respectively:
Burgess S.; Downey A. SFM1 Sap Flow Meter Manual. 2014. Version 4.0. University Of Western Australia. ICT International Pty Ltd
2) Checking in-text reference citations was cumbersome. The journal's guidelines were not followed, according to which references should be numbered in order of appearance in the text and listed individually at the end of the manuscript, and in the text, reference numbers should be placed in square brackets [ ].
AA: it is done
