جستجوی مقالات مرتبط با کلیدواژه "interception loss" در نشریات گروه "جنگلداری"

The amounts of throughfall and interception loss are as significant as habitat suitability regarding to the tree selection for afforestation. Horizontal cypress (Cupressus horizontalis Mill.), Turkish pine (Pinus brutia Ten.), and chestnut-leaved oak (Quercus castaneifolia C.A. Mey.) have been mainly used in afforestation projects in the East of the Hyrcanian region. How these afforestations affect the precipitation components and water balance of the region, however, is obscure. The main objective of this study was to measure throughfall and interception loss of Horizontal cypress and Turkish pine afforestation as well as of a natural stand of chestnut-leaved oak, over a period of 12 months starting from May 2012. One rain gauge and four rain collectors were placed in an open area adjacent to the study area in order to measure precipitation. To measure throughfall, thirty five throughfall collectors were randomly installed under the canopy of each stand. The amount of gross precipitation was 1135 mm over the study period. Throughfall measurements for planted Horizontal cypress and Turkish pine, and for natural stand of chestnut-leaved oak, were 439.4, 642.7, and 614.7 mm, respectively. Interception loss estimated to be about 61%, 43%, and 46% of gross precipitation in the above mentioned species, respectively. The positive and statistically significant relationships were found between throughfall and gross precipitation for the investigated stands, and then were parameterized with the power regression model. The identical procedure was applied as well for interception loss and gross precipitation for the stands. The analysis showed that considerable amounts of gross precipitation were intercepted by the canopy cover of the study stands and subsequently evaporated into the atmosphere. Since the species used for afforestation has significant influences on the amount of water reached to the ground, throughfall and interception loss should be considered in the process of choosing the species.

Measurements of gross rainfall (GR)، throughfall (TF)، and stemflow (SF) were conducted during the summer 2009 beneath a natural pure stand of oak (Quercus castaneifolia C. A. M) forest canopy located near the southern border of Kheyrud Forest Station of Tehran University. Measurements were made inside a plot with an area of 0. 12 ha. GR was collected by means of three manual collectors placed in a neighboring open area away from the study plot. Thirty five TF manual collectors were randomly positioned underneath the tree canopies. SF was collected from nine oak trees with different diameters by the spiral-type SF collection collars installed at diameter at breast height. All the measurements were performed on a rainfall event basis using a graduated cylinder. Interception loss (I) was calculated indirectly as the differ rence between GR and the sum of TF and SF. During the study period، 10 events were recorded. The cumulative GR، TF، SF، and I depths were 257 mm، 192 mm، 0. 7 mm، and 64. 3 mm، respectively. At the event scale average ratios of TF: GR، SF: GR، and I: GR were 72. 2%، 0. 2%، and 27. 6%، respectively. A weak correlation was observed between SF: GR and GR (r2 = 0. 43) while a fairly strong positive correlation was observed between I: GR and GR (r2 = 0. 65). Interception loss contributes a remarkable amount of incident rainfall in the studied oak forest and its measurement is an essential element in assessing water balance on a catchment scale.

At forest ecosystems, gross rainfall (GR) is partitioned into throughfall (TF), stemflow (SF) and results in canopy interception loss (CIL). In the present research, CIL, which is considered a major component of the water balance, was measured at the midland of the central Caspian forests, Kheyrud forest research station of University of Tehran. Measurements were carried out in a sample plot of pure oriental beech (Fagus orientalis Lipsky) stand with an area of 5625 m2. GR was collected using three manual collectors in an open area approximately 160 m apart from the study plot. Thirty six TF manual gauges were randomly placed beneath the beech canopies and SF was collected from six beech trees with different diameters by means of the spiral type SF collection collars installed at diameter at breast height. GR, TF and SF were collected on an event basis using a graduated cylinder during the summer season of 2008. The amount of cumulative GR depth of 19 events was 206.8 mm allocated to TF, SF and CIL, 135.5, 4.2 and 67.1 mm, respectively. At the event scale, the mean values of TF, SF and CIL were accounted 64.7, 1.6 and 33.7% of GR, respectively. Regression analysis suggested a strong positive relationship between CIL and GR. There was also observed a fairly weak negative relationship between CIL/GR and GR. We concluded that CIL contributes a remarkable amount of incident rainfall in the pure oriental beech forest of the study site and therefore should be considered in assessment of water balance.