Needle trace method

Needle trace method retrospectively records the needle age at the time of its fall-off and studies the influence of the environmental and biotic factors on needle proxies. Data on height increments and number of needle traces in tree-rings of individual growth shoot are collected. With needle proxies, the tree crown’s physical condition is evaluated. The method was developed in Finland on Scots Pine (Pinus sylvestris L.) and soon used on many other conifers. Its application is in dendrochronology, forest ecology, pathology and entomology. In this paper, the structure of needle trace is described, background of the method, its usage and the needle proxies: relative number of needle traces, needle retention, needle loss, needle shed, needle age, needle longevity, needle density, needle production and needle poo