Estimation of Yield Loss Due to Deer Browsing in a Short Rotation Coppice Willow Plantation in Northern Japan

Hisanori Harayama,Shozo Sasaki,Qingmin Han,Hajime Utsugi,Yutaka Maruyama,Mitsutoshi Kitao,Takeshi Yamada,Akira Uemura,Makoto Ishihara

doi:10.3390/f11080809

Hisanori Harayama, Shozo Sasaki + Show 7 more

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https://doi.org/10.3390/f11080809

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Abstract

Deer browsing is a major factor causing significant declines in yield in short rotation coppice (SRC) willow, but the resultant yield loss is difficult to estimate because it requires extensive investigation, especially when the standard yield is unknown. We investigated a simple method for estimating yield loss due to deer browsing. We enclosed an experimental SRC willow plantation in Hokkaido, northern Japan, planted with 12 clones, with an electric fence; deer browsing did, however, occur in the first summer of the second harvest cycle. We counted the number of sprouting stems and deer-browsed stems per plant and, after three years, the yield of each clone was analyzed using a generalized linear model with the above two parameters for the numbers of stems as explanatory variables. The model explained the yield of 11 out of the 12 clones, and estimated that browsing of a single stem per plant could reduce yield to 80%. Losses due to deer browsing were estimated to be as much as 6.0 oven dry ton ha−1 yr−1. The potential yield in the absence of deer browsing ranged from 2.2 to 7.5 oven dry ton ha−1 yr−1 among clones, and was significantly positively correlated with the estimated yield loss due to deer browsing. Our results suggest that a generalized linear model can be used to estimate the yield loss due to deer browsing from a simple survey, and deer browsing could significantly reduce willow biomass yield from the clones we studied, and thus countermeasures to control deer browsing are therefore necessary if sufficient willow biomass yield is to be produced.

Highlights

Global warming, which is mainly attributable to greenhouse gases such as CO2 [1], has recently led to increased efforts to utilize woody biomass energy from managed forests, which are treated as carbon neutral, in Europe and the United States [2,3], as well as in Japan [4]
Estimation of Yield Loss Caused by Deer Browsing
It was possible to predict the yield only by the data on the numbers of stems. These results suggest that when an short rotation coppice (SRC) willow plantation is damaged by deer browsing, the biomass loss can be estimated using a generalized models (GLMs) by counting the number of browsed and unbrowsed stems per plant and measuring the yield in places where the degree of of rotation

Summary

Introduction

Global warming, which is mainly attributable to greenhouse gases such as CO2 [1], has recently led to increased efforts to utilize woody biomass energy from managed forests, which are treated as carbon neutral, in Europe and the United States [2,3], as well as in Japan [4]. Short rotation coppice (SRC) willow is the most successful woody biomass energy crop in the cool temperate regions of Europe and North America [5,6,7,8,9,10]; under favorable conditions, it typically yields a biomass of over 10 oven dry ton (odt) ha−1 yr−1 , with a harvest rotation interval of 2–5 years. This capacity is associated with the coppicing ability of willow, which produces multiple stems and vigorous post-harvesting regrowth from the stump, resulting in repeated biomass yields of 20–50 odt ha−1 every 2–5 years over a Forests 2020, 11, 809; doi:10.3390/f11080809 www.mdpi.com/journal/forests. This is because of risks and uncertainties concerning its production, management, and marketing, which need to be resolved if the use of SRC willow is to be promoted [18]

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