Exploring the Impact of Thinning Operations on Forest Ecosystems in Tropical and Temperate Regions Worldwide: A Comprehensive Review

Thinning is a major tending operation conducted in a forest stand to obtain various objectives, including forest products and ecosystem services. The impact of thinning in tropical and temperate forests is one of the least studied subjects. Therefore, this study aims to look for such studies in the tropical and temperate regions and find out the trend in the response of the remaining trees regarding tree growth and development, climate resilience, and other services. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) framework and Population, Intervention, Comparison, and Outcome measures (PICO) tools were used to select the important papers according to defined objectives and then data extraction and analysis. Extracted data was grouped, pooled, and sorted to see if there were any temporal or spatial trends or patterns in the variables studied, and the reviews' findings were detailed. The impacts on the growth and yield of a forest or stand from thinning have been widely studied throughout the world. However, there are still some uncertainties regarding species-specific responses. This review also underscores the need for studies on the effects of thinning on other ecosystem services, including non-wood forest products, biodiversity, social functions, and tradeoffs between different ecosystem services. The study stresses the importance of long-term trials for forest ecosystem monitoring. Furthermore, analysis on the impact of thinning on other ecosystem services except growth and yield discovered that the few researches conducted to date, especially as regards to biodiversity and provisioning functions, must focus on a large number of ecosystem services without only concentrating on the components described in past studies. This will help us to develop our understanding of different ecosystem services and their responses after thinning and enable us to analyze the trade-offs between them. While managing forests, we cannot maximize all the services at the same time. However, with the best available knowledge on tradeoffs between different outcomes, we can optimize the benefits.