Within-tree, between-tree, and geospatial variation in estimated Pinus radiata bark volume and weight in New Zealand

Glen Murphy,Dave Cown

doi:10.1186/s40490-015-0048-5

Abstract

Many studies have been carried out to quantify the wood properties of radiata pine, but few have explicitly looked at quantifying radiata pine bark. Bark is of increasing interest for many reasons, e.g. energy source, potential source of bioproducts, log handling methods and costs, and phytosanitary methods. Over-bark and under-bark diameter measurements recorded from over 1000 discs taken from fixed heights in 150 trees were used to estimate bark volume percentages. The mature trees were from a single seed source and had been planted at 17 sites throughout New Zealand. Bark volume percentages were converted to bark weight percentages using data from 390 trees from the central North Island of New Zealand. This study confirmed earlier research that bark accounts for 12 to 13 % of over-bark volume and 7 to 8 % of over-bark green weight for mature radiata pine boles prior to felling and log handling. It also showed that bark volume percent varied with location in a stem, tree size, and site (mean annual temperature).

Highlights

Many studies have been carried out to quantify the wood properties of radiata pine, but few have explicitly looked at quantifying radiata pine bark
The term bark refers to all tissues of a woody stem or root occurring just outside of the vascular cambium, i.e. all tissues that could be stripped away from the woody core
Bark formation is initiated by the process of cell division at the living cambium, which separates the woody stem from the phloem, the food-conducting tissue on the exterior side

Summary

Introduction

Many studies have been carried out to quantify the wood properties of radiata pine, but few have explicitly looked at quantifying radiata pine bark. The term bark refers to all tissues of a woody stem or root occurring just outside of the vascular cambium, i.e. all tissues that could be stripped away from the woody core. Bark formation is initiated by the process of cell division at the living cambium, which separates the woody stem (xylem on the inside) from the phloem, the food-conducting tissue on the exterior side. Bark is critical to tree survival, serving two very important functions. The outer, mostly dead tissues (outer bark), form a protective barrier between the plant axis and the abiotic (wind, rain, fire, frost, and physical damage) and biotic (insects, fungi, herbivores) environment. Biomass of traditionally non-commercial components such as broken tops, dead trees, bark, needles, and branches is becoming important for carbon accounting, landscaping products, animal

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