Vegetation patterns in mature plantations of Pinus radiata and Pseudotsuga menziesii: Implications for forest transitions
Year: 2024
Type: article
Abstract: Non-harvest plantation forests are becoming more prevalent throughout the forestry industry for the purposes of carbon sequestration, facilitation of ecological restoration, or due to the establishment of plantations in sensitive environments where harvesting is no longer viable. The future of such forests is uncertain and there is increasing desire to transition these forests to native forest cover without clearcut of the plantation. We used vegetation data from eight older (>40 years) abandoned exotic plantation stands, four of Pinus radiata and four of Pseudotsuga menziesii in the Hawke’s Bay region of Aotearoa New Zealand to (1) examine the structure and composition of the understorey vegetation in the plantation stands, (2) explore the influence of extrinsic environmental variables and the plantation characteristics on plant communities, and (3) connect these relationships and dynamics to the practical management of non-harvest plantation forests. Vegetation composition data were analysed using ordination, including the fit of environmental vectors. Generalised linear mixed-effects models were used to analyse the effects of plantation and environmental variables on understorey vegetation composition and structure. The communities of native understorey vegetation were distinctly different between P. radiata and P. menziesii stands, however neither plantation species produced significantly higher native species richness or importance value. Linear mixed effects modelling found plantation species, age (+), and stocking (stem density) (-) to have the greatest effect on native understorey species richness (r2 = 0.44) and importance value (r2 = 0.43). All stands sampled contained native canopy tree species, while P. menziesii stands had dominant understorey cover of Melicytus ramiflorus and Fuscospora fusca, stands of P. radiata had dominant cover of Kunzea ericoides and Pterophylla racemosa. Both plantation species sampled showed potential for succession towards a native dominant forest, however, 43% of P. radiata stands were found to have exotic self-seeded conifers in the understorey suggesting the need for ongoing intervention. Although Podocarpaceae and Nothofagaceae species were found throughout the stands sampled, they were more sparse and less dominant than the native broadleaf species indicating that disturbance of the exotic canopy may be required for further growth and establishment of these emergent canopy species.
Source: Forest Ecology and Management
Authors: Grace R. Marshall, Bruce Manley, Sarah V. Wyse
Institution: University of Canterbury
Language: English
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
SDGs: Life on land, Climate action
Open Access status: hybrid
Estimated APC paid: $3,460
OpenAlex ID: W4402309895