PICOP revisited in 1993

agricultural purposes especially in Mindanao and Indonesia. For example, it is estimated the more than 60 percent of the finest stands on the Caliawan River, an east-bank tributary of the Agusan River in Mindanao has been destroyed ahead of agricultural activity. This destruction is continuing and, unless the stand is reserved for seed collection purposes, it will be virtually non-existent in a few years. This is one of the largest riverain stands in Mindanao and has been used by the Bislig Bay Lumber Company as a seed source. This particular provenance has been determined to be one of the best for forestry purposes in ecologically similar areas.”

In the present day I would add under the heading of “agricultural purposes” the rapid expansion of oil palm plantations in the lowland tropics as one of the risk factors threatening the survival of native stands of E. deglupta, especially on New Britain in PNG.

1993

PICOP revisited in 1993

Provenance trial of E. deglupta at PICOP. Keravat provenance on the left, local provenance on the right.

Eight-hectare block of E. deglupta, 11-years-old, set aside as a preservation stand of good seed source derived from locally collected seed. (Photographs: N Zabala)

Clone bank of E. deglupta at PICOP in 1993. The unusual shape of the trees had resulted from repeated cutting in the past to make marcots and lopping to rejuvenate the stem low down to produce coppice shoots from which to make cuttings. (Photograph: N Zabala)

Clone bank of E. deglupta♀ x E. pellita♂ hybrids 4.12 ha in area planted in September 1988 and photographed about four years later. Recent cutting back of the trees had allowed new coppice shoots to form about one meter or less above the ground. One or two lateral branches had been left to nurture the hedged stump. Low down some of these branches also produced sprouts. The coppice shoots and sprouts arising at this height in E. deglupta were physiologically juvenile and enabled cuttings from them to be struck with close to 100% success. (Photograph: N Zabala)

Scaffolding erected by PICOP around elite trees of E. deglupta to enable control pollination in situ with pollen from E. pellita and E. urophylla. Right: Clonal plot of the hybrid E. deglupta♀ x E. pellita (Tree No. 1)♂ at PICOP planted 12 May 1989 and photographed at age 3.5 years. This cross was best at the time in terms of height and diameter growth, relatively high wood density, and resistance to leaf blight, kino disease and varicose borer (Agrilus sp) attack. At 19.9 m in height and 16.4 cm in diameter by age 4 years the hybrid was twice as tall and 60% greater in diameter than the parents at that age. (Photographs: N. Zabala)