Puunkasvun

Puunkasvun is Finnish for the growth of timber or wood and refers to the increase in wood volume produced by trees or a forest stand over time. It is a central concept in forestry, used to describe the productive capacity of a stand and to forecast timber yields, biomass production, and forest-based energy resources. Puunkasvun is typically expressed as volume growth (for example cubic meters of wood per hectare per year) or as biomass growth.

Growth is determined by multiple factors. Species and genetic potential set the baseline, while site quality, climate, and soil moisture govern realized growth. Stand structure, including age, density, and spacing, strongly influences how trees compete for light, nutrients, and water. Management actions such as thinning, pruning, and altering rotation length can modify puunkasvun by reducing competition and improving wood quality and harvest age.

Measurement and modelling rely on growth indicators. Current annual increment (CAI) measures the wood volume produced in the latest year, while periodic annual increments (PAI) track changes over longer intervals. Growth is estimated from forest inventories using measurements of diameter at breast height (DBH), tree height, and age, combined with allometric equations and volume tables. Remote sensing and growth models are increasingly used for larger-scale assessments.

Economic and ecological implications are central. Puunkasvun informs sustainable harvesting schedules, carbon accounting, and bioenergy planning, while also interacting with biodiversity, pest risks, and climate change. Proper management aims to maximize productive growth while maintaining stand health and long-term forest resilience.