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Wiek rębności w lesie normalnym oraz lesie celowym

100%

Klocek A., Piekutin J.

Sylwan

2015

tom 159

nr 12

The paper focuses on the deterministic model of normal forest, the probabilistic model of target forest and the processes related to the survival and mortality of forest stands suitable for these models. They are the basis for the assumptions, presented in this paper, of two different methods of regulating rotation age adequate for normal forest and target forest. Optimizing the rotation age of a stand is essential for the regulation of forest production. It aims to establish such an age−dependent state of stand, which is the most desirable from the point of view of the adopted forest management objectives. Because of the long−term cycle of stand development, optimizing the age at which a stand is considered mature for felling usually means maximizing the average annual increase in stand volume. Under the conditions of normal forest, the concept formulated in the first half of the nineteenth century, the above optimization criterion has the form of the equation [2]. The current annual increase of timber production (P b(tu)) at the optimal rotation age (tu) is equal to the average annual increment (Pp(tu)). At this age, the intensity (rate) of the current growth of the production function (Pb(tu)/P(tu)) becomes equal to the fraction of the stand area (1/tu). These relationships are illustrated in figure 3. The model of target forest is derived from the random nature of two opposing processes described as 'survival' and 'mortality' of forests. This is reflected in the transition probability matrix where a forest stand moves from the younger age class to the older or to the youngest age class. The probability function (U(t)) of stand survival in individual management periods (t) developed on the basis of these data, is one of the main parameters of the optimization equation for the rotation age of target forest [11]. Formula [13] indicates that the optimal rotation age (t=tu) is when the rate of growth in the volume of merchantable timber (Pb(t)/P(t)) and the negative growth rate (decline) for a part or the entire stand (Ub(t)/U(t)) are equal to a fraction of the stand area. These interactions are illustrated in figure 8, which additionally presents the effect of the decline in the survival rate on the optimal rotation age (tu). This age may be analyzed separately for natural disasters and for clear−cutting of stands in accordance with the forest management plan. These two categories of effects may also be dealt with jointly

Macierzowe ujecie rozwoju lasu

100%

Klocek A., Oesten G.

Prace Instytutu Badawczego Leśnictwa

1992

nr 738-745

3-32

Ograniczanie wyników

1 Prace Instytutu Badawczego Leśnictwa

1 Sylwan

2 Klocek A.

1 Oesten G.

1 Piekutin J.

1 2015

1 1992

Wyniki wyszukiwania

Wiek rębności w lesie normalnym oraz lesie celowym

Macierzowe ujecie rozwoju lasu