methane and CO 2 fluxes by keeping the groundwater level low without inhibiting the
sago palm growth.
17.3.4 Trunk and Sucker
There is a comparatively large variation in trunk length even in a single folk variety.
Moreover, in general understanding, we suppose that trunk diameter of sago palms
growing in tropical peat soils will be smaller than those growing in mineral soils.
Yamamoto et al. (2003b) mentioned that the breast height diameter of sago palms
growing in tropical peat soils was smaller than those growing in mineral soils. At a
sago palm plantation where uniform species were densely planted in peat soils on
Tebing Tinggi Island, Riau, Indonesia, the earliest flowering spiny sago palm group
had trunk length ranging from about 8 to 10 m. That being said, there was a
significant variation for a small number of tree trunks which had length only of
4–5 m long (Jong 2015a). Yamamoto et al. (2003b) reported that the trunk height
increased 1.34 m/year and its volume increased 0.166 m
3 /year for sago palms
growing in mineral soils. On the other hand, the maximum of 2.2 m/year for the
trunk height increase rates and 0.29 m
3 /year for the trunk volume increase was found
on sago palms grown in peat soils with higher water table (Sasaki et al. 2007).
Kakuda et al. (2015) explained that the difference in the former reports might
indicate that the growth rate of the sago palm grown in peat soils with higher
groundwater level exceed that of sago palm grown in mineral soils.
Suckers mostly emerge from their parent trunk near the groundline. They grow
and form a thicket around the parent trunk or often creep sideways and form trunks
away from their parent trunk (Watanabe et al. 2015). Watanabe et al. (2015)
explained that long creeping suckers were found more often in the areas of hard
mineral soils on riverbanks than in the soft peat soil areas in Mukah Malaysia.
17.3.5 Growth Phase
Sago palm is a monocarpic and hapaxanthic plant, producing flowers and fruits only
once in its life cycle. In Sarawak, Malaysia where peat soils stretch, the sago palm
life cycle is divided into 12 growing stages from rosette stage up to withering stage;
stages 7–9 correspond to the appropriate harvest time (stage during which the trunk
reaches maximum length, just before the emergence of inflorescence up to the
flowering stage) (Yamamoto 1998). On the contrary, Osozawa (1990) reported
that the life cycle is divided into eight growing stages in the Indonesian province
of South Sulawesi; here the proper harvesting time is considered to be between stage
3 (when a white bloom appears at the base of the petiole following trunk formation)
and 5 (when the trunk reaches the final length and the petiole becomes white) which
is slightly earlier than in Sarawak. Generally, a sago palm grows best in mineral
17 Sago Palm in Peatland
487
sago palm growth.
17.3.4 Trunk and Sucker
There is a comparatively large variation in trunk length even in a single folk variety.
Moreover, in general understanding, we suppose that trunk diameter of sago palms
growing in tropical peat soils will be smaller than those growing in mineral soils.
Yamamoto et al. (2003b) mentioned that the breast height diameter of sago palms
growing in tropical peat soils was smaller than those growing in mineral soils. At a
sago palm plantation where uniform species were densely planted in peat soils on
Tebing Tinggi Island, Riau, Indonesia, the earliest flowering spiny sago palm group
had trunk length ranging from about 8 to 10 m. That being said, there was a
significant variation for a small number of tree trunks which had length only of
4–5 m long (Jong 2015a). Yamamoto et al. (2003b) reported that the trunk height
increased 1.34 m/year and its volume increased 0.166 m
3 /year for sago palms
growing in mineral soils. On the other hand, the maximum of 2.2 m/year for the
trunk height increase rates and 0.29 m
3 /year for the trunk volume increase was found
on sago palms grown in peat soils with higher water table (Sasaki et al. 2007).
Kakuda et al. (2015) explained that the difference in the former reports might
indicate that the growth rate of the sago palm grown in peat soils with higher
groundwater level exceed that of sago palm grown in mineral soils.
Suckers mostly emerge from their parent trunk near the groundline. They grow
and form a thicket around the parent trunk or often creep sideways and form trunks
away from their parent trunk (Watanabe et al. 2015). Watanabe et al. (2015)
explained that long creeping suckers were found more often in the areas of hard
mineral soils on riverbanks than in the soft peat soil areas in Mukah Malaysia.
17.3.5 Growth Phase
Sago palm is a monocarpic and hapaxanthic plant, producing flowers and fruits only
once in its life cycle. In Sarawak, Malaysia where peat soils stretch, the sago palm
life cycle is divided into 12 growing stages from rosette stage up to withering stage;
stages 7–9 correspond to the appropriate harvest time (stage during which the trunk
reaches maximum length, just before the emergence of inflorescence up to the
flowering stage) (Yamamoto 1998). On the contrary, Osozawa (1990) reported
that the life cycle is divided into eight growing stages in the Indonesian province
of South Sulawesi; here the proper harvesting time is considered to be between stage
3 (when a white bloom appears at the base of the petiole following trunk formation)
and 5 (when the trunk reaches the final length and the petiole becomes white) which
is slightly earlier than in Sarawak. Generally, a sago palm grows best in mineral
17 Sago Palm in Peatland
487