Tropical forest area is disappearing at the rate of 13.5 million ha each year, due mainly to clearing for agriculture and shifting cultivation. Timber harvesting results in more than 5 million ha of tropical forest annually being transformed into degraded, poorly managed, logged-over forests. The reduction and degradation caused by anthropological activities affect not only the sustainable production of timber but also the global environment. Accurate scientific information will enable managers to devise silvicultural systems to enhance soil properties and forest resources important for sustainable production and to minimize deleterious impacts of harvesting and short rotation plantations. Ultimately, rehabilitation can increase the area of forest as well as conserve remaining primary forests and environmental quality. Rehabilitation aims to improve biological diversity, increase commercial value of timber and non-timber products, increase forest functions and improve soil fertility. Technical advances will reduce logging impacts, accelerate natural regeneration and improve species selection, enrichment, sustainable site management, catalytic planting and site evaluation and classification. Socio-economic reform should focus on local community participation and acceptance. The CIFOR/Japan project has undertaken research in many countries to evaluate impacts of harvesting and fires on forest ecosystems and to develop methods to rehabilitate logged-over forests and degraded forestlands in ways that are biologically successful as well as socio-economically acceptable. In Indonesia, CIFOR collaborates with Universitas Mulawarman at the Bukit Soeharto Education Forest, a mixed dipterocarp forest logged by INHUTANI I in 1976. The approach to rehabilitation has been through the "taungya" system whereby farmers grow annual crops among newly planted trees. With the Instituto Nacional de Investigacion Agraria (INIA), Peru, the project is trialling revegetation of fallow fields abandoned after agricultural use in the Ucayali region of the Peruvian Amazon. There is specific interest in selecting tree species with high economic value that grow rapidly in abandoned agricultural land and on infertile soils. Early results point to promising species. The project also involves small farmers in silvicultural activities and species selection.
Kwa mfano, misitu ya kitropiki inapotea kwa wastani wa hekta milioni 13.5 kila mwaka, hasa kwa sababu ya uharibifu wa misitu kwa ajili ya kilimo na uhamisho wa kilimo. Kwa mfano, kila mwaka, zaidi ya hekta milioni tano za misitu ya kitropiki hubadilishwa kuwa misitu iliyoharibiwa, isiyodhibitiwa vizuri, na iliyokatwa. Kupungua na uharibifu unaosababishwa na shughuli za kibinadamu huathiri si uzalishaji endelevu wa mbao tu bali pia mazingira ya kimataifa. Taarifa sahihi ya kisayansi itawawezesha wasimamizi kubuni mifumo ya kilimo cha misitu ili kuboresha mali za udongo na rasilimali za misitu muhimu kwa uzalishaji endelevu na kupunguza athari mbaya za kuvuna na mashamba ya mzunguko mfupi. Hatimaye, ukarabati unaweza kuongeza eneo la msitu na pia kuhifadhi misitu ya msingi iliyobaki na ubora wa mazingira. Urekebishaji wa misitu una lengo la kuboresha utofauti wa kibiolojia, kuongeza thamani ya kibiashara ya mbao na bidhaa zisizo za mbao, kuongeza kazi za misitu na kuboresha uzazi wa udongo. Maendeleo ya kiufundi yatapunguza athari za ukataji miti, kuharakisha urekebishaji wa asili na kuboresha uteuzi wa spishi, utajiri, usimamizi endelevu wa tovuti, kupanda kwa kichocheo na tathmini na uainishaji wa tovuti. Marekebisho ya kijamii na kiuchumi yanapaswa kuzingatia ushiriki wa jamii za mitaa na kukubalika. CIFOR na Japan wamefanya utafiti katika nchi nyingi ili kutathmini athari za kuvuna na moto kwenye mifumo ya mazingira ya misitu na kuendeleza mbinu za kurudisha misitu iliyokatwa na misitu iliyoharibiwa kwa njia ambazo zinafanikiwa kiikolojia na pia zinakubaliwa kijamii na kiuchumi. CIFOR inashirikiana na Universitas Mulyawarman katika Msitu wa Elimu wa Bukit Soeharto, msitu mchanganyiko wa dipterocarp uliochimbwa na INHUTANI I mnamo 1976. Njia ya kurekebisha imekuwa kupitia mfumo wa "taungya" ambapo wakulima hukua mazao ya kila mwaka kati ya miti iliyopandwa hivi karibuni. Pamoja na Taasisi ya Kitaifa ya Uchunguzi wa Kilimo (INIA), Peru, mradi huo unajaribu urekebishaji wa mashamba ya udongo yaliyokuwa yameachwa baada ya matumizi ya kilimo katika mkoa wa Ucayali wa Amazon ya Peru. Kuna maslahi maalum katika kuchagua spishi za miti na thamani ya juu ya kiuchumi ambayo kukua kwa kasi katika ardhi ya kilimo iliyokuwa imeachwa na juu ya udongo usio na rutuba. Matokeo ya mapema yanaonyesha kwamba kuna spishi zenye kuahidi. Mradi huo pia unahusisha wakulima wadogo katika shughuli za kilimo cha misitu na uteuzi wa spishi.