Dear. Editor

The current paper aims to parameterize i) allometric questions for aboveground biomass using an existing database and ii) an equation to estimate woody debris on the forest floor using data based on field survey, for Siberian Larix cajanderi.

Authors demonstrate significant spatial variations of biomass of standing trees and woody debris estimates on the forest floor, depending on equations and parameters, comparing their estimated parameters with published ones. They come to the conclusion that the developed functions can be applicable to the species in Siberian forests.

I consider that the paper would fail to fit within the journal’s scope as well as may fail to attract a broad readership, because i) the study develops a tool, with no application of the tool, thus to fail to draw geo- or biological conclusion, ii) even the developed tools are only appliable at a relatively small scale, as no testing for the feasibility of a large scale application was made, while such tools for a large scale application already exist from national to continental scales, and iii) the estimated parameters were unjustly compared with published parameters, as to overfitting and comparing between different population distributions; for example, published equations were based on smaller and older trees, compared to the data set, based on which allometric questions were developed.

Here come specific comments.

L 15. “… at breast height (DBH)”

Depending on regions, the breast height differs. Specify the height (m).

L51. “The line-intersect…”

Authors may begin a new paragraph before “The line- …”

2.1 Fine woody debris sampling

This section may be expanded and articulated. For example, papers that have been cited here (Sackett 1980; Van Wagner 1982; Nadel et al. 1997; 1999) articulate the formulation. Because the formulation is of great importance in the paper, it has to be well explained, and readers would not want to check back those papers to understand the formulation and meanings of parameters.

L130. Volume of a sample was first dried and then estimated. Would it underestimate volume of the sample due to shrinkage during drying?

L 305. Figure 3.

I would recommend to add data points in the figures. Ranges of the independent variable (DBH) differ significantly between functions. For example, DBH in Yakutia ranges 1.9 – 18.9 cm, while DBH in Magadan ranges 3.9 – 52.8 cm. Comparing and merging two populations, each of which has a different DBH distribution, may result in a bias outcome. Moreover, it is invalid to compare it with other published studies, where the populations of size and age of sample trees were out of the current study samples’ distribution.

L325. Figure 4.

The meaning of error bars needs to be explained. And how can the estimates of aboveground biomass be 0 (lower ending of the estimates are all 0)?

The authors of Allometric equations and wood density parameters for estimating aboveground and woody debris biomass in Cajander larch (Larix cajanderi) forests of Northeast Siberia observed mean squared diameter and specific gravity. They developed allometric equations at 25 sites in the Republic of Sakha in Russia. They then make comparisons to allometric equations developed in other studies. Overall the methods appear rigorous. This study provides valuable information from an important yet remote region of the world from which little in-situ data is available and makes the case that further data collection efforts are needed. My major concern is that the claim that the allometric equations presented in the text are more generally applicable needs to be better supported or more nuanced. The equations and the comparison of them to other previously developed equations are not validated against in situ data or across a larger region of space. It seems that the equations from earlier work would be more applicable than those developed by the authors in some more northeastern regions or specific stand types, especially near where they were developed. This is very problematic given the manuscripts focus on providing generalized equations to improve our ability to estimate above-ground biomass in this region.

L95 introduction: I suggest highlighting some of the other roles that this data could play (previously mentioned around L35) to strengthen the introduction.  

L140: Is there a citation for the two equations above. Also, some brief explanation of why the samples were dipped in paraffin could be useful.

L205-210: I suggest including a bit more information about this fitting method and selecting the exponent c, including references to other work that uses this method. It could also be useful to include these residual plots in the appendix.

Figure 3: It would be good to include the data points on this plot where possible and the standard error envelopes for the fits. These lines are also somewhat difficult to distinguish when printed in black and white.

L206: I think table A1 is important and merits inclusion in the text. It could be interesting to see this comparison done differently. For example, calculating fuel loads at one of the study sites using these different parameters and then plotting the values could better illustrate their importance in percentage terms.  

L310: The Magadan site has many more samples than the Yakutian site, although the size range of the available samples varies. Given the conclusion that allometry is somewhat region-specific, it could be interesting to see the result of a fit where this imbalance of samples is corrected using weighting.

Figure 4: For this box plot of the site observations, it would be good to explain the quantiles, etc. shown in the figure caption

L315: Some additional summary information for these 53 sites could be useful (i.e., the mean, sd, and range of dbh)

L315-320, 350-365: I suggest heavily revising these sections of the paper. The claim that the other allometric equations underestimate aboveground biomass or are more generally applicable seems too strong. The actual aboveground biomass of the 53 comparison sites is not truly known. From the text or maps, it's unclear where exactly these test sites are located and how close they are to the sites from Siewert 2015. The comparison to Siewet 2015 is not emphasized in the text. This point would be much stronger if some additional non-allometry-derived data sources, more information from the literature, etc., were included as validation. It could also be interesting to see this comparison done across multiple sites. I imagine these other two equations will perform better in certain areas or stand types. Such a comparison would add more depth to the point about how generalizable each set of equations is.

L330-340: Interpreting the fitted allometric parameters (i.e., as in Niklas 1994) here and further discussing the differences in climate and other properties between the sites could strengthen the conclusions in this section.

This manuscript describes the size-class-dependent characteristics of fine woody debris according to their detailed field experiment, and the new allometric relationship by using literature data, for the Cajander larch forest in Northeast Siberia. Since such data in this region (central Yakutia) is limited, this manuscript will contribute a lot to future modeling and remote sensing studies in this region. I've already seen the comments from the two reviewers and the author's replies, so I'd like to add some minor comments about what I'm still unsure about.

About fine woody debris:

The authors show the MSD and specific gravity of Cajander larch for each diameter size class.

On the other hand, they compared their single factor M with other species in different regions in Table A1, but it is shown in the percentage difference by size class, not the actual values of M. I think the single factor M and the fuel load W can be the important outcomes of this study, so I suggest the authors show these results.

Equation (1):

• Even though the final answer is correct, I strongly suggest you adopt the consistent units in the equation. Specifically, the unit of QMD should be [m], not [cm], and the equation should be multiplied by 10⁴ to convert the unit from [Mg m^-2] to [Mg ha^-1]. This will avoid confusion by the readers and avoid careless mistakes in calculation.
• Secant (sec) should be in non-italic.
• Is G_i the arithmetic mean of G (specific gravity) within the diameter size class i?
• Is h_i the arithmetic mean of h (piece tilt angle) within the diameter size class i? If yes, is it mathematically correct to calculate the secant using the arithmetic mean value of h for obtaining the fuel load?
  • For example, If h takes 0 degrees and 180 degrees, the arithmetic mean of them can be 90 degrees.
  • Besides, according to Fig. 2, h is always related to the diameter of each sampled piece, so I think the product of the diameter and sec h should be used for the statistical calculation.
• If N represents the (total) number of intercepts over the length of the transect line, what does N_i mean?

Equation (2):

• I suggest using a single character (e.g., α) instead of "slope" to represent the ground slope.
• (tan α)² is generally written as tan²α.

Equation (3) and L140:

• The authors use two characters to represent the specific gravity. One is G in equation (1) and L104 (kg m^-3), and another is S here (g cm^-3).

L158-159, equation (5):

• Does a single factor M represent the fuel loads per intercept (sample) on the transect line? Please explain this concept concisely since the reference (Nalder et al., 1999) was not accessible from my environment.
• If you share the same units with equation (1), G_i has the unit of [Mg m^-3], and MSD_i might have the unit of [cm²]. However, the author specified that M has the unit of [g cm^-1]. In this case, the units of the left and right sides of equation (5) are inconsistent. I suppose the unit of G_i in equation (5) would be [g cm^-3], or it should be S_i according to equation (3).
• As pointed out in equation (1), I still wonder whether the use of “sec h_i” is mathematically correct if h_i represents the arithmetic mean of h in class i.