A Range-Wide Experiment to Investigate Nutrient and Soil Moisture Interactions in Loblolly Pine Plantations

Rodney E Will ,Madison Akers,Geoffrey Lokuta,Asko Noormets,Cassandra Meek,Daniel Markewitz,Jason B West ,Mary Anne Mcguire ,Michael B Kane ,Eric J Ward ,Thomas R Fox ,Jean‐Christophe Domec ,Robert O Teskey ,Marshall A Laviner ,Jason G Vogel ,Dennis Wilson ,Lisa J Samuelson ,Carlos A Gonzalez‐Benecke ,Eric J Jokela ,Brian D Strahm ,John R Seiler ,Timothy A Martin

doi:10.3390/f6062014

Abstract

The future climate of the southeastern USA is predicted to be warmer, drier and more variable in rainfall, which may increase drought frequency and intensity. Loblolly pine (Pinus taeda) is the most important commercial tree species in the world and is planted on ~11 million ha within its native range in the southeastern USA. A regional study was installed to evaluate effects of decreased rainfall and nutrient additions on loblolly pine plantation productivity and physiology. Four locations were established to capture the range-wide variability of soil and climate. Treatments were initiated in 2012 and consisted of a factorial combination of throughfall reduction (approximate 30% reduction) and fertilization (complete suite of nutrients). Tree and stand growth were measured at each site. Results after two growing seasons indicate a positive but variable response of fertilization on stand volume increment at all four sites and a negative effect of throughfall reduction at two sites. Data will be used to produce robust process model parameterizations useful for simulating loblolly pine growth and function under future, novel climate and management scenarios. The resulting improved models will provide support for developing management strategies to increase pine plantation productivity and carbon sequestration under a changing climate.

Highlights

Pine (Pinus taeda L.) is one of the most important commercial tree species in the world, and is the foundation of the forest products economy of the southeastern USA, which produces 16% of the world’s timber volume, more than any other country [1]
The objective of this paper is to describe a novel regional research project that measures the early growth response of loblolly pine plantations to throughfall reduction and fertilization at four locations spanning the commercial range
At two of the four sites throughfall reduction reduced growth, and at the other two sites, the effect was not significant. This result indicates that the effects of a drier climate on loblolly pine plantation growth may be modest in some regions, with effect size varying with location, regional weather patterns, edaphic features, and water table depth

Summary

Introduction

Pine (Pinus taeda L.) is one of the most important commercial tree species in the world, and is the foundation of the forest products economy of the southeastern USA, which produces 16% of the world’s timber volume, more than any other country [1]. Even with application of intensive silviculture to increase growth rates, rotation lengths of loblolly pine plantations in the southeastern USA are usually longer than 20 years [3]. To respond to projected changes in climate, a better understanding is needed of how climate affects loblolly pine plantation growth, productivity, and resilience. This information can be used to adapt forest management to novel climate conditions and help mitigate the rise in atmospheric greenhouse gases through increased carbon sequestration

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Results

Conclusion