KLÍMA-21 Füzetek 61. szám - VAHAVA Hálózat

„KLÍMA-21” FÜZETEK: KLÍMAVÁLTOZÁS – HATÁSOK – VÁLASZOK 191
For the 21 st Century, climate models predict drastic narrowing of the climatic niche of
climate sensitive species, resulting in loss of yield and a decline in profitability. The planned
increase of forest area by afforestation seems to be insufficient to counter the worsening of
climate – at least according to our present knowledge.
Increased data collection by monitoring and the development of modelling techniques are
necessary to obtain a more realistic picture about the multiple roles of forests in climate protection.
Long-term strategies depend on reliable data to support climate-oriented forestry and
nature conservation. Results will also affect how the society perceives the role of forests and
forestry.
TREE GROWTH AND THE CLIMATE
By
FÜHRER, ERNŐ
Keywords: climate change, growing of trees, forestry aridity index.
The improvement of forest management practices depends foremost on the new approach
of assessing the ecological and forest site factors of forest landscapes as part of an eco-system.
In this system, climate has become a dynamically changing factor of the forest site.
The available eco-physiological observations and the biomonitoring of forests as a function
of the climate have clearly shown that the water supply in the main growing cycle and main
utilisation period (fifth to seventh months) and in the critical months (seventh and eighth)
has a decisive effect on the growing and vitality of forests. The cause and effect relationship
between climatic conditions and the increase in trunk diameter may be characterized using
the simplified „forestry aridity index” /FAI/. The default value of the index is as follows: FAI
: 100 x TØVII-VIII /(PV-VII + PVII-VIII).
This means that with the help of the „forestry aridity index” /FAI/ we can characterize the
general climate of climate classes used in forestry practice and that of any place or region
from a forestry aspect. That is to say beech forest climate is found in areas characterized with
a value of 4.75 or lower. Hornbeam-oak forest climate occurs is associated with an FAI value
between 4.75 and 6.00, Turkey oak-sessile oak forest climate FAI value is between 6.00 and
7.25, while forest-steppe climate has an FAI value higher than that.