Jurnal Penelitian Hasil Hutan

186-192

Authors: Djarwanto

Five wood species namely tangkalak (Litsea roxburghii Hassk.), cangkring (Erythrina fusca Lour.), kayu putih (Melaleuca cajuputi Powell.), ki tanah (Zanthoxylen rhetsa D.C.), and huru leueur (Sterculia cordata Blume.), were evaluated based on their metal corrosion properties using jam-pot methods. Wood samples were extracted from two tree stands, divided radially into three groups, namely outer, middle and inner part of log. The results showed that iron corrosion was found in all wood species. The corrosion intensities were identified by the weight loss of the attached metal screws. Higher corrosion rates were found on samples of kayu putih. The highest weight loss of screw was found on kayu putih samples extracted from midle part (B part) of P-II tree, i.e. 2.76%. The lowest weight loss of screw was encountered on tangkalak wood samples extracted from inner part (C part) of P-II tree. The percentage of samples weight loss on tree-I was lower (0.55%) than that on tree-II i.e. 0.72%. Comparing those two sample groups, the weight loss of outer part (A) and inner part (C) were lower than that of the middle part of logs.

200-212

Authors: Sona Suhartana, Yuniawati & Dulsalam

As of this occasion, the management of timber harvesting at the peat-swamp plantation-forest in practice still has not yet reached the optimal tree felling plot area. Consequently, this necessitates exploring a representative model to determine meticulously such optimal plot area, thereby ensuring the forest management to proceed in a sustainable way. In relevant, the related study was carried out consecutively in May 2012 at the PT Wira Karya Sakti's concession area in Jambi; and in June 2012 at the PT Riau Andalan Pulp & Paper's concession area in Riau. For such, the necessary data were taken descriptively and pur posively, which comprised the felling-plot areas (X) and the costs (Y) for skidding, maintenance, and canal erection. Further, the obtained X-Y data couples were analyzed for possible quadratic regression models. Results revealed that in Jambi the X-Y model came-up in the regression equation as Y =254.82 - 10.98 X + 0.21 X2 (R2 =0.43**), with the optimum felling area (X) equal to 26.69 ha and the minimum cost for skidding, maintenance, and canal erection (Y) reaching 105.32 (in Rp 1,000,000,000). Correspondingly, in Riau, the X-Y appeared as Y=299.47 - 14.85 X + 0.26 X2 (R2 = 0.59**), with the optimum felling area (X) reaching 28.60 ha and the minimum cost (Y) as much as 87.14 (in Rp 1.000.000.000).

221-227

Authors: Sukadaryati & Dulsalam

The increased demand of pine resin both for domestic and overseas markets has necessitated efforts to enhance pine-sap production. The use of strong acid-based conventional stimulants has been long employed by Perum Perhutani, but questions arise regarding the environment effect as well as growth survival of the tapped pine trees. Consequently, the use of biostimulant deserves thorough consideration, since not only will assure friendly-environmental effects but also securing the sustainability of the pine trees. An experiment was conducted to look into the effect of using biostimulants on the production of sap (exudates) from the tapped pine trees. Three tapping techniques were employed, i.e. mujitech, boring and kedukul. The biostimulant consisted of three kinds (lengkuas, kencur, and red onion), each with three concentration levels (50%, 75%, and 100%). It turned out different tapping techniques seemed not affecting the pine-sap production, nor did the effect of biostimulant concentrations (50-100%). However, different kinds of biostimulants did so, whereby lengkuas afforded the sap-yield increase the highest (268%) compared to the control (without biostimulants), followed in order by kencur (206%) and red onion (180%). Use of the second and third caused no significant difference. Economically, the use of lengkuas biostimulant at 50% concetration was effective enough. Further attempts are neseccary to find other alternative biostimulants.