Effect of strip shelterwood-cuts on the crown morphology plasticity of natural regenerated Pinus tabuliformis saplings in northeastern China

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Effect of strip shelterwood-cuts on the crown morphology plasticity of natural regenerated Pinus tabuliformis saplings in northeastern China https://t.co/19GDl3P9WM @thePeerJ https://t.co/7s1yu1miCy
Plant Biology

Main article text

 

Introduction

Materials and Methods

Study area

Data collection

Parametric regression approach for the crown profile model

where OCR is the outermost crown radius within the crown, RDINC is the relative depth into the crown of interest, and a1a3 are the model parameters to be estimated.

where the base X is a function of RDINC, the point of inflection p and the two other parameters c1 and c2 are variables to be estimated. The OCR is zero at the tip of the tree when RDINC equals zero and reaches the maximum, that is the largest crown radius at the point of inflection when RDINC equals p.

RMSE=Mi=1nij=1(OCRijOˆCRij)2n1
where R2=1Mi=1nij=1(OCRijOˆCRij)2/Mi=1nij=1(OCRijOˉCRij)2, OCRij is the outer crown radius of the jth branch from the ith sapling, OˆCRij is the predicted outermost crown radius of the jth branch from the ith sapling, M is the number of saplings, and ni is the number of branches from the ith sapling.

QYi(τ|xi)=g(xi,β0(τ))
ˆβn(τ=argminbBρτ(yig(xi,b))
where OCRij is the outer crown radius of the jth branch from the ith sapling, f(·) is the nonlinear equation form, X represents the variables, θ represents the parameters, and εij is the error term.

Outermost crown profile description for the saplings

where a and b are the lower and upper endpoints, respectively, of the design points RDINC1,…, RDINCn, where n indicates the number of divisions for the interval of [a, b]. In the present study, a equalled 0, and b equalled 1 according to the biological characteristics of the crown. The optimal polynomial degree was obtained by minimising AIC and BIC. The nonparametric boundary estimator and the optimal polynomial degree were estimated by the new R software package ‘npbr’ (Abdelaati, Thibault & Hohsuk, 2017; Koenker, 2018).

Effect of shelterwood-cut strips on the crown morphology plasticity of saplings

Results

Basic model selection for the outermost crown profile

where OCR is the outermost crown radius within the crown, DBH is the diameter at breast height, CR is the crown ratio, a1a5 are the parameters to be estimated, and the other variables are defined as those above.

where c1c5 are the parameters to be estimated, and the other variables were defined as those above.

Outermost crown profile model development using nonlinear quantile regression

Comparison of crown morphology for saplings between shelterwood-cut and uncut strips

Discussion

Conclusions

Supplemental Information

Sapling characteristics and branch length measurement.

A total of 49 and 30 saplings from clear-cut and uncut strip were provided. The sapling sample branch was selected from each whorl of each saplings were measured for the annual branch length.

DOI: 10.7717/peerj.9826/supp-1

Additional Information and Declarations

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Huilin Gao conceived and designed the experiments, performed the experiments, analysed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, and approved the final draft.

Jian Feng conceived and designed the experiments, analysed the data, authored or reviewed drafts of the paper, and approved the final draft.

You Yin conceived and designed the experiments, authored or reviewed drafts of the paper, and approved the final draft.

Wanjin Hu conceived and designed the experiments, performed the experiments, prepared figures and/or tables, and approved the final draft.

Yang Qu performed the experiments, prepared figures and/or tables, and approved the final draft.

Mingguo Liu performed the experiments, authored or reviewed drafts of the paper, and approved the final draft.

Data Availability

The following information was supplied regarding data availability:

The raw data are available as a Supplemental File.

Funding

This work was financially supported by the talent introduction funding for scientific research start-up from Shenyang Agricultural University (Project No. 880418014) and general project of Liaoning provincial department of education (Project No. LSNQN201901). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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