Karakteristik Biofisik pada Ekosistem Hutan Pendidikan Gunung Walat dan PT Gunung Walat Perkasa

Abstract

Kawasan Gunung Walat, Sukabumi, mengalami perubahan tutupan lahan akibat aktivitas pertambangan pasir kuarsa oleh PT Gunung Walat Perkasa. Perubahan ini diduga memengaruhi kondisi ekosistem Hutan Pendidikan Gunung Walat (HPGW). Penelitian bertujuan menganalisis perbedaan karakteristik biofisik antara HPGW, area semak belukar, dan lahan tambang. Penelitian dilaksanakan Desember 2024–Februari 2025 dengan purposive sampling pada tiga tipe lahan: hutan tanaman puspa, semak belukar, dan lahan tambang. Data yang dikumpulkan meliputi analisis vegetasi (kerapatan, jenis, tutupan tajuk), pengambilan sampel tanah (profil, sifat fisik-kimia-biologi, serasah), serta pengukuran iklim mikro (suhu, kelembapan, intensitas cahaya). Analisis dilakukan di laboratorium dan diolah dengan uji statistik seperti korelasi Pearson dan Analisis of Variance (ANOVA). Hasil penelitian menunjukkan perbedaan mencolok antar tiga tipe lahan. Hutan tanaman puspa memiliki kondisi terbaik dengan kerapatan vegetasi tertinggi 239.800 ind/ha, enam jenis tumbuhan (antara lain puspa Schima wallichii, kayu afrika, teki, wedellia, paku rane, dan harendong), kerapatan tajuk 81,31%, solum tanah >100 cm, horizon O 10,33 cm, serasah kering 488 g/m² (daun) dan 23 g/m² (batang), warna tanah very dark brown, bulk density rendah, porositas baik, pH mendekati netral, dan kandungan C-organik tinggi, iklim mikro juga stabil dengan suhu dan kelembapan sejuk serta intensitas cahaya rendah. Semak belukar menempati posisi menengah dengan sekitar 73.325 ind/ha, kerapatan tajuk 78,38%, solum >100 cm, horizon O 2,67 cm, serasah kering 169 g/m² (daun) dan 21 g/m² (batang), warna tanah dark yellowish brown, dan kondisi fisik–kimia sedang. Lahan tambang paling terdegradasi, hanya memiliki 32.500 ind/ha dengan satu jenis tumbuhan (Arthraxon prionodes), kerapatan tajuk 0%, solum rata-rata 33,67 cm, tanpa horizon O dan serasah, warna tanah dark grayish brown, bulk density tinggi, porositas rendah, pH masam, C-organik sangat rendah, serta iklim mikro terpanas dengan kelembapan terendah dan cahaya penuh. Hasil ini menegaskan bahwa aktivitas pertambangan mengakibatkan kerusakan signifikan pada vegetasi, tanah, dan kestabilan iklim mikro. Aktivitas pertambangan menyebabkan degradasi signifikan pada struktur tanah, keanekaragaman vegetasi, dan stabilitas iklim mikro. Hutan tanaman puspa terbukti menjaga kondisi biofisik yang jauh lebih baik dibandingkan semak belukar dan lahan tambang, menegaskan pentingnya rehabilitasi hutan dan good mining practices

The Gunung Walat area in Sukabumi has experienced land-cover changes due to quartz sand mining activities by PT Gunung Walat Perkasa. These changes are suspected to affect the ecosystem of the Gunung Walat Educational Forest (Hutan Pendidikan Gunung Walat, HPGW). This study aimed to analyze differences in biophysical characteristics among the HPGW, shrubland, and mining sites. The research was conducted from December 2024 to February 2025 using purposive sampling across three land types: a puspa (Schima wallichii) plantation forest, shrubland, and mined land. Data collection included vegetation analysis (density, species composition, canopy cover), soil sampling (profile, physical–chemical–biological properties, litter), and microclimate measurements (temperature, humidity, light intensity). Analyses were carried out in the laboratory and processed with statistical tests such as Pearson correlation and Analysis of Variance (ANOVA). The results revealed significance differences among the three land types. The puspa plantation forest had the best conditions, with the highest vegetation density of 239,800 individuals/ha; six plant species (including puspa Schima wallichii, African mahogany, sedge, wedelia, paku rane, and harendong); 81.31% canopy cover; soil depth >100 cm; O-horizon thickness of 10.33 cm; dry litter of 488 g/m² (leaves) and 23 g/m² (branches); very dark brown soil color; low bulk density; good porosity; near-neutral pH; and high organic-carbon content. Its microclimate was also stable, with cool temperatures, high humidity, and low light intensity. Shrubland showed intermediate conditions, with about 73,325 individuals/ha, 78.38% canopy cover, soil depth >100 cm, O-horizon thickness of 2.67 cm, dry litter of 169 g/m² (leaves) and 21 g/m² (branches), dark yellowish brown soil, and moderate physical–chemical properties. The mined land was the most degraded, supporting only 32,500 individuals/ha with a single plant species (Arthraxon prionodes), 0% canopy cover, an average soil depth of 33.67 cm, no O-horizon or litter, dark grayish brown soil color, high bulk density, low porosity, acidic pH, very low organic-carbon content, and the hottest, driest microclimate with full sunlight exposure. These findings confirm that mining activities have caused significant degradation of vegetation, soil structure, and microclimatic stability. The puspa plantation forest clearly maintains far superior biophysical conditions compared with shrubland and mined land, underscoring the importance of forest rehabilitation and the implementation of good mining practices.