Relascope sampling for crown ratio estimation

Autor:	Sebastian Schnell, Jonas Wikman, Göran Ståhl
Rok vydání:	2013
Předmět:	Global and Planetary Change Observational error Ecology biology Thinning Forest Science Crown (botany) Scots pine Sampling (statistics) Estimator Forestry biology.organism_classification Basal area Statistics Range (statistics) Mathematics
Zdroj:	Canadian Journal of Forest Research. 43:459-468
ISSN:	1208-6037 0045-5067
DOI:	10.1139/cjfr-2012-0230
Popis:	In this study, we apply vertical angle count sampling to estimate the crown ratio of trees in unthinned forest stands. The rationale is to be able to quickly assess the relative crown size of forest stands to support thinning decisions by simply counting trees. We provide estimators and discuss their precision based on pilot studies in Scots pine (Pinus sylvestris L.) plantations in northern Sweden. A separate study was conducted to investigate the amount of measurement errors, i.e., how many trees are wrongly selected or overlooked when using the method. Sampling errors for estimating crown ratio were found to be remarkably low, partly due to high correlation between crown length and tree height and partly due to low variability in the study sites. Measurement errors were in the range of what is commonly obtained with horizontal angle count sampling for basal area estimation.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8f8c14aa666a22b064a01ab911b9d5db https://doi.org/10.1139/cjfr-2012-0230 Zobrazit plný text záznamu Plný text ve formátu PDF