Projecting Monterey Pine (Pinus radiata) Populations over Time in the Presence of Various Representations of Pitch Canker Disease, Caused by Fusarium circinatum

Gregory J Reynolds,Neil Mcroberts,Thomas R Gordon

doi:10.3390/f10050437

Abstract

Monterey pine (Pinus radiata D. Don) is native to California and widely planted in Mediterranean climates around the world. Pitch canker, a disease caused by Fusarium circinatum Nirenberg and O’Donnell, is a serious threat to P. radiata in native forests and in plantations. Because of its economic importance worldwide, conservation of P. radiata native populations is a high priority. We developed a demographic matrix projection model to simulate dynamics of naturally occurring P. radiata populations in California in the presence of the disease. Tree demography data for the model were collected from seven sites in a native forest on the Monterey Peninsula. Height and stem diameter were recorded for all trees, which were divided into five size classes based on these data. Transition probabilities were calculated for each size class; cone production, seed release, and seed transition probability were estimated using an iterative search process. In the model, pitch canker influences state-specific fecundity and survival probabilities. Five different approaches to include these effects were compared. Populations were projected over 50 decades from three specified initial population sizes. Elasticity analysis indicated that facilitating survival of all size classes is vital to maintaining the structure of the forest.

Highlights

IntroductionDon) is one of the most widely grown tree species in the world
It is native to the central coast of California, where its range has shifted over time with climate change [1]
Proportions of trees of each size class to the overall population at each site varied between sites; for example, large saplings and mature trees accounted for 24% of trees in Indian

Summary

Introduction

Don) is one of the most widely grown tree species in the world. It is native to the central coast of California, where its range has shifted over time with climate change [1]. Native populations are currently restricted to three locations on the central coast of California and two Mexican islands off Baja California. Monterey pine has been extensively planted internationally, in Spain, New Zealand, Australia, and Chile, and is grown on over 4.2 million hectares [2]. Because of its importance to worldwide timber production and relatively limited native range, native populations in California are an important source of genetic diversity [3].

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