Sains Malaysiana 39(2)(2010): 181–187

Pengaruh Kanopi Hutan Sekunder Terhadap Kadar Pintasan bagi Kitaran Hidrologi di Tasik Chini, Pahang, Malaysia

(Influence of Secondary Forest Canopy towards Interception Rate in Hydrological Cycle of Tasik Chini, Pahang, Malaysia)

Nor Rohaizah Jamil^{*, 1}, Mohd Ekhwan Toriman²

Mushrifah Idris¹ & Lim Wei Jing¹

¹Pusat Pengajian Sains Sekitaran dan Sumber Alam

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

²Pusat Pengajian Sosial, Pembangunan dan Persekitaran

Fakulti Sains Sosial dan Kemanusiaan, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

Received: 29 October 2008 / Accepted: 3 August 2009

ABSTRAK

Sebahagian hujan akan diperangkap oleh lapisan kanopi pokok dan permukaan lain sebagai pintasan, sebelum tersejat kembali ke atmosfera. Air hujan menuruni kanopi hutan melalui dua mekanisme; aliran batang dan jatuhan langsung. Aliran batang merujuk kepada jumlah air hujan yang sampai ke permukaan tanah dengan menuruni batang pokok dan dahan. Manakala jatuhan langsung pula merujuk kepada jatuhan terus air hujan yang menembusi lapisan kanopi hutan melalui ruang-ruang antara daun dan menitis dari daun, cabang dan dahan pokok. Kedua-dua komponen ini dinilai menggunakan plot pintasan bersaiz 100 ¥100 m2 di hutan sekunder Tasik Chini. Tiga puluh batang pokok telah digunakan dan setiap pokok dikenal pasti berdasarkan spesies, famili, diameter aras dada (DBH) saiz kanopi dan ketumpatan kanopi. Dalam kajian ini, data pintasan telah dikumpulkan pada dua kali kejadian hujan yang berlaku dalam bulan November 2007 (44.51% dalam bentuk jatuhan langsung dan 55.49% dalam bentuk aliran batang) dan taburan hujan dalam bulan Disember 2007 (39.65% dalam bentuk jatuhan langsung dan 60.35% dalam bentuk aliran batang). Kajian pintasan ini menghasilkan maklumat penting bagi kitaran hidrologi yang berlaku dalam ekosistem hutan, juga keseimbangan air tanah bencah.

Kata kunci: Aliran batang; hutan sekunder Tasik Chini; impak hidrologi; pintasan; spesies tempatan natif

ABSTRACT

Part of a rainfall is captured by the crowns of the trees and other surfaces as interception, which is then evaporated back into the atmosphere. Water moves down through the forest canopy via two mechanisms; stemflow and throughfall processes. Stemflow refers to the total quantity of rain water which reach the ground through tree stems and branches. Throughfall in the other hand, is the tendency of the rainfalls to penetrate the forest canopy directly through the spaces between the leaves or by dripping from the leaves, twigs, and branches. Both components were measured in an interception plot size 100 ¥100 m2 in a secondary tropical forest at Tasik Chini. Thirty tree samples were used and each tree was well-identified based on their species, family, diameter breast height (DBH), canopy size and its density. In this study, the data were collected based on two rainfall events, namely in November 2007(44.51% in throughfall form and 55.49% in stem flow form) and rainfall distribution on December 2007 (39.65% in throughfall form and 60.35% in stem flow form). This interception study provided essential information on how the function of the forest can affect the crucial hydrological cycle occurring within this forest ecosystem and the wetland water balance.

Keywords: Hydrological impact; interception; native local species; stem flow; Tasik Chini secondary forest

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*Corresponding author; email: norrohaizahjamil@yahoo.com