**1. Introduction**

The timber and timber-based products are the fourth largest contributor to Sarawak's export earnings after natural gas, petroleum and palm oil products. The timber industry, in particular, contributed to RM6.31 billion (USD 1.43 billion) in royalty, premium and cess revenue over a ten-year period, from 2010 to 2021. In addition, it also provides employment, creates business opportunities and facilitates road access for the rural communities that subsequently support eradication of poverty and sustainable development of the country.

Log supply from the natural forests peaked in the 1990s at about 20 million m<sup>3</sup> and declined to 4.07 million m3 in 2019. The concern for the sustainability of natural forests has become a major topic of discussion these days. Sarawak is committed to conserving a healthy forest environment for the long term, including biodiversity conservation and

ecosystem functioning with an aim to strike balance between the development and economic needs of the nation. Sarawak has a total land area of approximately 12.4 million hectares of which 7.7 million hectares or 62 per cent is under forest cover. Under the 'Sarawak Land Use Policy,' 7 million hectares have been allocated for sustainable forestry and conservation. Out of these, 6 million hectares are Permanent Forest Estates (PFEs) and 1 million hectares are Totally Protected Areas (TPAs). The remaining 5.4 million hectares are for agriculture and other development purposes. Under the Sarawak Forest Policy, the key component is sustainable forest management (SFM). SFM is implemented based on the guidelines in the Forest Statement Policy 1954.

Sarawak embarked on large-scale forest plantations in 1996 as a long-term strategy to provide a new source of wood material for the State's wood-based industries. Hitherto, Sarawak is the main player in Malaysia's forest plantation industry in the county where the total area of its plantation forests reached 551,704 hectares with three (3) main species planted, dominated by *Acacia* (55%), *Falcataria moluccana* (19%) and *Eucalyptus* (14%). Sarawak hopes to establish one (1) million hectares of industrial forest by 2025 by planting fast-growing species. It is hoped to produce 15 to 25 million m<sup>3</sup> a year when the target is achieved. In addition, the planted forest will relieve pressure on logging in natural forests in terms of both area size and intensity.

Currently, the forest plantation area could only produce an average production yield per ha of 70–120 m3 assuming fully stocking at the age of 8 years trees. However, to better secure the future wood supply that Sarawak needs for its domestic and international markets, the production yield per ha should be increased to an average of 120–210 m3 to be on par with other timber-producing countries such as Vietnam, China and Indonesia. One of the major attributes that had been identified in contributing to the poor growth and performance is the occurrences of disease attacks as well as the unavailability of genetically improved planting materials that are disease-resistant.

The research effort on forest health in Sarawak is still in the infant stage; however, its capacity has increased over the past decade. Surveys and basic quantitative evaluations were conducted during the period 20152020 in response to the plantation development observed in Sabah and Indonesia. Surveys and evaluations for forest health are crucial, and they should be conducted immediately and systematically in order to obtain related information such as disease incidence, signs and symptoms, contributing factors, and pathogens as well as silviculture treatments.

This information is expected to be used by stakeholders and policy-makers in developing an appropriate disease management strategy to control the disease infection on their plantations. Hence, this is the first baseline study conducted to identify and evaluate the incidence and the damages of the known major diseases as well as the emerging disease that could pose a threat to the vitality of forest plantation tree species in Sarawak.

The significant information gathered from this study will definitely provide an overview of the risk and threats of the pathogens and the management options that could be undertaken for a countermeasure.
