Download Кабінет Міністрів України

General information
The presentation of the results of the work done: send the file of the work done,
using the means of MS Word through Elearn.
Evaluation criteria:
10 points - total.
7 points - correct interpretation and clarity of design.
3 points - timeliness of presentation of the work and the validity of the findings.
Deadlines results: for the next class after the explanation for the work.
Practical work 1 (2 hours)
Topic: Forest and its components. Differentiation of trees in a forest
The purpose: Describe the components of forest, characterize the natural
thinning of the stand during growth, estimate the state of the forest and propose
measures to improve it.
Objectives
1. Explain the definition of the term "forest", give a list of components and
their characteristics.
2. Describe the classification of trees in stands for Kraft classes for normal
growth and development of pure stands.
3. Analyze the differentiation of trees in stands and propose of the necessary
measures to improve it state.
Order performance
Forest is an important component of the biosphere that supports its stability,
provides self-cycling of matter and energy, as well as performs other ecological
functions. There is definition in the standard "Forestry. Terms and definitions" – a
forest is an element of geographical landscape, which consists of a combination of
land, trees, occupying a dominant position, shrubs, over-ground cover, animals
and microorganisms in their development are interrelated, affecting each other
and the environment [1].
Forests are covered large areas, resulting in significant impact on the
environment. Classic of forest science G. Morozov claimed that the forest and
its territory should be combined into a single unit, and that the forest should be
considered as a geographical phenomenon [2].
2
Trees in the forest, even the same species and same age, are significantly
differed in size and shape of trunks and crowns. These may include wood various
stages of development: the great and powerful medium development and poorly
developed and declining. This phenomenon is observed in the stands on
homogeneous soils and in the same climatic conditions. The most common
classification of trees in a stand is considered the Kraft’s classification. According
to classification, all the trees of the growth and development conventionally
divided into normal developed (dominant) and retarded in growth (subordinate).
The main features for classification of tree to serve the dominant or subordinate to
the following: the nature of the crown, tree height and position it among the
neighboring trees. The most important feature here is the shape and development
of the crown, which define the process of photosynthesis.
The specified features all the trees are divided into five classes (Fig. 1).
Fig. 1. Classification of trees for growth and development
Class I – to dominated trees are relatively large trees that dominate over
others, with the largest diameter trunks and crown strongly developed,
characterized by intense growth (usually in a plantation of trees is up to 10%);
Class II – the dominated trees, with well-developed crown and slender trunk
(the number is in the range 20-40%);
Class III – sub dominated trees, characterized by equally tall trees of the
second class, but with compressed adjacent by tree canopy crown, there are signs
of oppression (their number is about 20-30%);
Class IV – suppressed trees – viable trees with poor growth, with narrowed
and often non-developed crowns (the number in plantation may be up to 30%).
3
Trees fall into this class IVa class - a tree with evenly branched crown and IVb trees with unilateral (like flag) form of the crown;
Class V – dying and dead trees (of up to 10%), which stands under the
canopy and are divided into class Va - trees still viable with the crown and Vb dead (declined) tree.
The next step is the assessment of specific state of stand (data for the task is
taken from Annex 1). Set of trees of each share class and the data recorded in
Table 1.
1. Distribution of trees in a plantation by class Kraft
(Numerator, pieces / denominator, %)
Using these objectives and comparing them with the probable distribution of
Kraft plot (as a bar graph) and draw the appropriate conclusions (differences on the
theoretical and actual distribution of trees for the growth and development) with
obligatory justification (Fig. 2).
Fig. 2. Distribution histogram of trees in the stand
The ration of well developed trees is 84% (I + II + III). The ratio of
suppressed trees is 16% (suppressed trees with poor growth – IV class + dying and
dead trees – V class). Deviation of actual state of trees on the histogram in
comparison with normal distribution was in favor of healthy, well-developed trees.
The state of the stand is rated as excellent. So, there is no necessity to conduct any
thinning.
The paper substantiates the necessity of thinning on sequencing: urgent;
priority; the second stage; no need for cuttings.