Assessing forest yield and site suitability for Eucalyptus grandis x E. urophylla in coastal Zululand, South Africa, under climate change scenarios
Date
2022-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: This study aimed to project future mean annual temperature (MAT), mean annual precipitation
(MAP), species site suitability, forest yield and the risk of the Leptocybe invasa pest for Eucalyptus
grandis x urophylla (E. g x u) in coastal Zululand of South Africa, under two emission scenarios
(Representative Concentration Pathway (RCP) 4.5 and 8.5), each for the intermediate term (2041
– 2060) and long term (2081 – 2100). The study utilized projected future climate variables from
Global Circulation Models (GCMs) used in phase five of the coupled Model Intercomparison
Project (CMIP5) for use in the R version of 3PG (Physiological Processes Predicting Growth) to
simulate forest stand volume. The climate data was also combined with recorded presence of the
Leptocybe invasa pest to develop an ecological niche model using the Maximum Entropy
(Maxent) model and project the possible risk of the pests’ infestation in the study site. Generally,
projected future climates revealed increasing MATs amid reducing MAP over most of the study
points in both RCP 4.5 and 8.5 as well as shifts in species site suitability for E. g x u. After
validating and testing the r3PG model for use in coastal Zululand using field data, the r3PG runs
across the future scenarios projected a pattern of reducing volume yield for E. g x u. A second
species that was tested, Pinus elliottii, exhibited a relatively more severe trend of reducing yields
from the current scenario through the future scenarios. These projected changes were observed
amidst a reducing risk of L. invasa over the study grid points in both pathways by the end of the
century.
Even though the data had some inaccuracies, acquired from third party sources, and based on
assumptions from GCMs, this study shows how integrating projected climate information,
processed-based growth models and pest risk models can improve the information available to
South Africa’s Forest industry. The integration of these data and models could contribute to the
preparedness of the forest industry and inform policymaking towards mitigating uncertain climate
futures.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
Description
Thesis (MFor)--Stellenbosch University, 2022.
Keywords
Forest yield, Mean annual temperature, Forests and forestry -- South Africa -- Zululand, Eucalyptus -- South Africa -- Zululand, Forests and forestry -- Climatic factors -- South Africa -- Zululand, Forests and forestry -- Effect of temperature on -- South Africa, Global circulation models, Forests and forestry --Effect of climatic changes on, UCTD