Abstract. In a watershed, forest has important roles in relation with peak discharge. This research was conducted to study the impacts of teak forest on peak discharge. On-screen digitising of IKONOS imagery was done to classify the land cover of the study area. Kejalen and Gagakan catchments covered by 74% and 53% of old teak forests respectively, were chosen as the study areas.These catchments are located in Blora Regency. Automatic water level recorder was set at the outlet of each catchment subsequently, and peak discharges were examined from the recorded data. During the observation, there were 36 evidences of specific peak discharge. The results showed that a trend of lower peak discharges occurred in Kejalen catchment which has the higher percentage of teak forest area in compared to Gagakan catchment with lower percentage of teak forest area, except when extreme rainfalls happened. At rainfall of 163 mm/day, specific peak discharge in Kejalen was higher than in Gagakan catchment. Although there is a relationship between specific peak discharge and the percentage of forest cover area, the increase of specific peak discharge is not only affected by forest cover, but also affected by daily rainfall, antecedent soil moisture, and rainfall intensity. Coefficients of determination between specific peak discharge and daily rainfall are 0.64 and 0.61 for Kejalen and Gagakan catchments, respectively.Keywords: Peak discharge, teak forest, catchment. Abstrak. Persentase penutupan hutan Daerah Aliran Sungai (DAS) berperanan penting dalam menentukan puncak debit. Oleh karena itu telah dilakukan penelitian yang bertujuan untuk mempelajari pengaruh hutan jati (Tectona grandis) terhadap puncak debit. Klasifikasi penutupan lahan dilakukan dengan digitasi secara langsung pada citra IKONOS. Dua sub-DAS yaitu Kejalen dan Gagakan yang masing-masing arealnya tertutup hutan jati tua sebesar

Soil erosion and sedimentation are environmental problems faced by tropical countries. Many researches on soil erosion-sedimentation have been conducted with various results. Quantifying soil erosion-sedimentation and its temporal distribution are important for watershed management. Therefore, a study with the objective to quantify the amount of suspended sediment from catchments under various pine plantation areas was conducted. The research was undertaken during 2010 to 2017 in seven catchments with various percentage of pine coverage in Kebumen Regency, Central Java Province. The rainfall data were collected from two rainfall stations. A tide gauge was installed at the outlet of each catchment to monitor stream water level. The water samples for every stream water level increment were analyzed to obtain sediment concentration. The results showed that monthly suspended sediment of the catchments was high in January to April and October to December, and low in May to September. The annual suspended sediment fluctuated during the study period. Non-linear correlations were observed between suspended sediment and rainfall as well as suspended sediment and percentage pine areas. The line trend between suspended sediment and percentage of pine areas showed that the increase in pine areas decreased suspended sediment, with the slope of the graph is sharp at the percentage of pine areas from 8% to 40%, then is gentle for pine plantation areas more than 40%.

Spatial distribution of land properties and its susceptibility to degradation is essential for watershed management planning. Therefore, a study was carried out to assess spatial distribution of land susceptibity to degradation and provide some recommendations for its improvement. The location of the study was in the upper Solo sub-watershed which majority located in Central Java Province. To classify degree of land susceptibility, a watershed typhology was applied. The typhology of watershed was based on land system and land cover type. Data of land cover and slope steepness were derived from sattelite images. Land system was obtained from Regional Physical Planning Programme for Transmigration (RePPProT). The results show that 36% of the study area is covered by highly susceptible and 55% moderate susceptible to degradation. The rest are classified as very high, low, and very low suceptible to degradation. Improvement of the degraded land can be achieved by applying land use planning which is suitable with its capability, in fact agricultural areas are found at land use capability classes VI and VII which have to use for production forest and limited production forest. In addition, conservation practices need to be applied, especially for agricultural land at V st of land capability class.

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Tujuan penelitian ini adalah untuk (1) mengidentifikasi sektor ekonomi unggulan dan (2) menganalisis ketimpangan pendapatan antar kabupaten di Sub DAS Bengawan Solo Hulu. Penelitian dilakukan di 5 kabupaten: Wonogiri, Boyolali, Klaten, Sragen, dan Karanganyar. Analisis data menggunakan tipologi Klassen untuk mengetahui pola dan struktur ekonomi, Location Quotient (LQ) untuk mengidentifikasi sektor unggulan, Indeks Williamson untuk mengetahui disparitas ekonomi, dan kontribusi sektoral untuk mengetahui peran sektoral. Hasil penelitian menunjukkan bahwa sektor unggulan berbeda tiap kabupaten, yaitu Wonogiri (pengangkutan dan komunikasi), Karanganyar (industri pengolahan), Boyolali (keuangan, real estat, dan jasa perusahaan), Sragen (pertanian, peternakan, kehutanan, dan perikanan), dan Klaten (konstruksi). Sektor ekonomi unggulan di setiap kabupaten bervariasi tergantung ketersediaan sumberdaya dan keunggulan komparatif. Berdasarkan pola dan struktur ekonominya, Kabupaten Karanganyar termasuk daerah maju dan berkembang pesat tetapi Wonogiri termasuk daerah terbelakang. Hasil penelitian juga menunjukkan disparitas pendapatan antar daerah di masingmasing kabupaten terkategori rendah (0,25) dan cenderung meningkat. Kebijakan pembangunan ekonomi dengan pertumbuhan ekonomi tinggi dan disparitas rendah dapat dilakukan dengan pengembangan sektor unggulan secara inklusif dan memperhatikan transformasi ekonomi yang terjadi di tiap kabupaten Subdas Bengawan Solo Hulu, kabupaten, sektor unggulan, ketimpangan pendapatan 1 2