Scaling Approach for Estimating Stand Sapwood Area from Leaf Area Index in Five Boreal Species

Quiñonez-Piñón Quiñonez-Piñón,Valeo Valeo

doi:10.3390/f10100829

Abstract

This paper presents a scaling approach for estimating sapwood area at the stand level using knowledge obtained for individual trees of five boreal species: Populus tremuloides (Michx.), Pinus contorta (Doug. ex Loud. var. latifolia Engelm.), Pinus banksiana (Lamb.), Picea mariana (Mill.) BSP, and Picea glauca (Moench) Voss. Previously developed allometric models for sapwood depth and diameter at breast height for individual tree species were used to build stand level sapwood area estimates as well as stand level leaf area estimates, in pure and mixed vascular vegetation stands. A stand’s vegetation heterogeneity is considered in the scaling approach by proposing regression models for each species. The new combined scaling approach drew strong linear correlations at the stand scale between sapwood area and leaf area using observations taken in mixed stands of Southern Alberta, Canada. This last outcome suggests a good linear relationship between stand sapwood area and stand leaf area. The accuracy of the results was tested by observing each regression model’s adequacy and by estimating the error propagated through the whole scaling process.

Highlights

Sapwood area supports several physiological functions, such as photosynthesis, gas ex-change, cooling, nutrient transport, and transpiration
The objectives of this paper are: (1) To create reliable regression models—if adequate for each dataset—to estimate sapwood area at the breast height for Populus tremuloides, Pinus banksiana, Pinus contorta, Picea glauca, and Picea mariana; (2) to develop appropriate scaling LA-SA relationships for forest stands comprised of a mixture of these species; and (3) to determine the absolute error propagated while scaling sapwood depth from an individual tree up to the stand level
Since the accuracy of water balance components is crucial in this area of work, the authors believe that determining SA, SAplot, LA and LAplot propagated errors are fundamental to any such research and modelling

Summary

Introduction

Sapwood area supports several physiological functions, such as photosynthesis, gas ex-change, cooling, nutrient transport, and transpiration. Sapwood area has been theoretically related to leaf area with Shinozaki’s pipe model theory [1]. One-seeded Juniper (Juniperus monosperma (Engelmann) Sargent) [11]; and Balsam fir (Abies balsamea (L.). Muell.) [14]; Trembling aspen (Populus tremuloides) [10]; and Cherry bark oak (Quercus falcate Q.Pagoda) and Green ash (Fraxinus pensylvanica Marshall) [15]. In this last work, the model for predicting leaf area was improved by having sapwood area as a predictor, but by adding total height and live crown ratio to the model [15]

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Conclusion