Phenology is defined as study of visible phases of the growth cycles of tree species, their timing, lasting and development in connection to local conditions of the environment (changes in occurrence, start and end of individual phases, possible air pollution effect on the stands, mainly with respect to period and lasting of the exposition). The results obtained are used to evaluate actual state of individual trees, and the effect of the environment, e.g. changes and misbalances of meteorological factors. Within the intensive monitoring plots phenological observations are divided in two main parts:
- Development of individual phases of tree growth during the year,
- Occurrence of biotic and abiotic damage during the year
To get and complete the information on state and development of both individual trees and the whole stand during a year is the main objective of phenological observations. The data obtained are an important contribution in evaluation of the effect of climate changes on the forest ecosystems, mainly in connection to other data of intensive monitoring, as meteorological parameters, deposition, soil solution chemistry, health state and growth.
Phenological observation of one or more main tree species in the plot is done in two ways:
- On the tree level – individual selected trees are evaluated, preferably trees with dendrometers
- On the stand level – the whole plot is evaluated