Báo cáo lâm nghiệp: Diurnal and seasonal fluctuations in the bark respiration of standing Quercus acutissima trees in Nakaizu, Japan

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Diurnal and seasonal fluctuations in the bark respiration of standing Quercus acutissima trees in Nakaizu, Japan...
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Báo cáo lâm nghiệp: "Diurnal and seasonal fluctuations in the bark respiration of standing Quercus acutissima trees in Nakaizu, Japan"Diurnal and seasonal fluctuations in the bark respirationof standing Quercus acutissima trees in Nakaizu, JapanY. KakubariLaboratory of Silviculture, University of Shizuoka, Shizuoka, Japan Kakubari 1988). As a first step, the diurnalIntroduction and seasonal fluctuations in bark respi- ration from the stem were measured inTo compare annual carbon balances standing trees of red oak (Quercus acutamong different types of forest exosys- issima) in Nakaizu, Shizuoka Pref., Japan.tems or to study the relationship betweenphotosynthetic production and treegrowth, the amount of carbon fixed in pho-tosynthesis and the respiratory loss by Materials and Methodswoody organs must be known approxi-mately. The amount of information aboutbark respiration in field studies of woody The measurements of bark respiration were performed from March 1986 to May 1987 in aorgans of trees is especially limited. In 19 yr old coppice stand, felled 3 times before, insitu measurements on stem respiration Nakaizu (N 34°58’, E 139°1’, altitude 320 m),rates in trees have been made by Johans- about 95 km northeast of Shizuoka. The gen-son (1933), Negisi (1975), Linder and eral climate is characterized by abundant rain-Troeng (1981),Havranek (1985) and fall (approximately 3700 mm annually), and theannual average air temperature is 13.8°C. Bark many forest tree The increase of species.respiration was measured in 8 parts of stem rates is connected with the respirationbark at different heights of dominant (d) and fluctuations of xylem temperatures andsuppressed (s) trees, located at the edge (o) diameter growth (Linder and Troeng,and within ( the stand (Table I). ) * 1981; Havranek, 1985). The respiration chambers were enclosed withplates of stainless-steel forming cylinders. Airwas circulated over the enclosed bark surface Diurnal fluctuations in stem bark respira-at a flow rate of 800-3000 ml/min through inlet tion as related to temperature changesand outlet vinyl tubes attached to the respirationchamber. The xylem temperature was mea-sured with an iron-constantan thermocouple The diurnal fluctuations of stem bark res-inserted into the inner layer of the bark. Thebark respiration and air, xylem and soil tem- piration at 0.4, 6.4 and 12.4 m at the edgeperatures were monitored continuously with a of the stand on 30 July 1986 are shown inmeasuring system, connected with an interface Fig. 2 together with photosyntheticallyboard to an I/O processing unit and infrared gas active radiation, xylem and air tempera-analyzer (Kakubari, 1988). tures. The daily course of bark respiration was closely dependent upon xylem tem- perature changes throughout the day. InResults and Discussion the stem near the ground, the xylem tem- perature was constant at any time of day because of the cooling effect of the sapSeasonal fluctuations in bark respiration flow, corresponding to the soil tempera-rates in relationship to xylem temperature ture. With increasing heights, xylem tem- perature rose quicker during the day, and the difference between the daily maximumIn Fig. 1, bark respiration rates measured ...