Kota Kinabalu: Correct species selection can contribute up to 40 per cent of total yield gains in Industrial Tree Plantations (ITPs), said South African forestry and soils specialist Dr Colin Smith.
“Poor species-to-site matching remains one of the most common and costly mistakes in the industry,” said Smith, who has more than 40 years of international experience in commercial plantation forestry across Africa and Southeast Asia.
He said this during the “Best Operational Practices in Managing ITPs” session at the BFC Conference 2026: Designing Sustainable Industrial Tree Plantation Systems and Landscapes.
The conference, held at the Sabah International Convention Centre, is hosted by Borneo Forestry Cooperative (BFC) Research and Development Sdn Bhd.
Smith said that, among improvements in growth resulting from silvicultural practices, correct species matching to site conditions contributed 40 per cent of the total increase in pulp yield at the end of the rotation.
“I have seen a lot of failure in plantation forestry and very often it takes almost a full rotation to understand how we should have done it in the first place,” he said.
He said about half of Malaysia falls within the tropical lowland climate zone, with a mean annual temperature above 26 degrees Celsius, while 28 per cent is classified as tropical upland and 10 per cent as subtropical upland, which he said are more forgiving environments for plantation forestry.
“They are perfect in my view for growing Eucalyptus pellita,” he said, referring to the tropical upland zone that covers large parts of the country.
He cited a case in Central Africa where a company planted Eucalyptus grandis across 4,000 to 6,000 hectares, only for the trees to begin dying back after four to six years due to disease because the species was not suited to the local environment.
“The trees looked fantastic for about four years and all of a sudden it failed,” he said, adding that the plantation recovered only after the company switched to a more suitable species.
He said a similar case of dieback had also been observed in Sabah, where a Eucalyptus urograndis compartment failed at eight to 10 years of age, while Eucalyptus pellita planted nearby continued to grow well in the same environment.
“Correct species matching is not only at a soil or compartment level, it can also be at a macro level, and if we get this wrong and invest a lot of time and energy into incorrect species, it can also be an expensive business to turn the business around,” he said.
He said tropical environments in the region are generally characterised by high rainfall, high humidity and highly weathered, low-fertility soils that require correction with basic nutrients at planting.
“Sabah and Sarawak fall largely within tropical lowland and tropical upland climate zones, with the environment shifting towards subtropical conditions above roughly 550 metres in altitude,” he said, pointing out that the change significantly widens the range of species that can be grown.
“As soon as you get into a subtropical environment, especially with Eucalyptus, you start being able to grow a lot more different commercial species than you are in the tropical environment,” he said.
He said soil damage from harvesting operations is a serious and growing concern in Sabah and Sarawak, pointing out that compaction can quietly reduce plantation yields even when no visible damage is apparent.
“We used to see easily about 10 to 15 per cent reduction in growth on the impacted areas in South Africa year to year and you could not even see the damage,” he said.
He said Eucalyptus species are particularly vulnerable to compaction as up to 30 per cent of their carbon is stored underground through extensive root systems, making soil conditions at planting critical to long-term productivity.
He said BFC has developed a site classification system for Sabah, Sarawak and Peninsular Malaysia to guide species selection at regional, plantation and soil suitability levels, and that training on the system is ongoing.
He said Eucalyptus deglupta and Eucalyptus pellita are generally suited to hot, wet tropical lowland areas, while Eucalyptus urophylla hybrids perform better at higher, cooler altitudes. Species such as teak and gmelina require better-drained, less acidic soils with slightly higher potential of hydrogen (pH).
Acacia species, he said, are nitrogen fixers and are generally more tolerant of shallow and acidic soils, with Acacia crassicarpa able to withstand waterlogged conditions better than most other commercial species.
He said correct species choice and clone deployment remain critical to maximising the genetic and site potential of commercially valuable species used in ITPs.
“Site classification is a valuable tool to achieve strategic species deployment and yield optimisation in industrial tree plantations,” he said.