New findings on loblolly pine plantations from long-term experimental field studies
Pine plantations in the southern US have been among the most intensively managed forests in the world. Their productivity has been enhanced by intensive silvicultural treatments over the past 60 years, and our knowledge about their treatment response has been expanded through long-term large-scale experimental studies. The analysis of nine long-term loblolly pine (Pinus taeda L.) field trials resulted in several new findings. For loblolly pine in the southern US, there exist maximum productivity and maximum response to silvicultural practices. The maximum response was inversely proportional to the base site quality. The maximum stand basal area (BA) and maximum stand density index (SDI) were redefined for individual stands. The average maximum stand BA and maximum SDI were 46.2 m2 ha-1 and 1002 tph, respectively, and both showed significant variation (30.2– 61.7 m2 ha-1 and 600–1410 tph, respectively). Stand aboveground net primary production (ANPP) generally increased with increasing site quality, due to increased stand foliage biomass in the early stage, and mainly due to increased growth efficiency in the late stages of stand development. More intensive silvicultural treatments increased foliage biomass, thus increased ANPP at early ages; thereafter silvicultural intensity did not affect foliage biomass, ANPP, and growth efficiency. The trend of early age increases in both foliage biomass and ANPP resulting from increased planting density did not hold true with stand development. Keywords: pine plantation; maximum stand density index; maximum stand basal area; maximum response; intensive management ID: 3606017
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| Format: | Article biblioteca |
| Language: | English |
| Published: |
FAO ;
2022
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| Online Access: | https://openknowledge.fao.org/handle/20.500.14283/CC1399EN http://www.fao.org/3/cc1399en/cc1399en.pdf |
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| Summary: | Pine plantations in the southern US have been among the most intensively managed forests in the world. Their productivity has been enhanced by intensive silvicultural treatments over the past 60 years, and our knowledge about their treatment response has been expanded through long-term large-scale experimental studies. The analysis of nine long-term loblolly pine (Pinus taeda L.) field trials resulted in several new findings. For loblolly pine in the southern US, there exist maximum productivity and maximum response to silvicultural practices. The maximum response was inversely proportional to the base site quality. The maximum stand basal area (BA) and maximum stand density index (SDI) were redefined for individual stands. The average maximum stand BA and maximum SDI were 46.2 m2 ha-1 and 1002 tph, respectively, and both showed significant variation (30.2– 61.7 m2 ha-1 and 600–1410 tph, respectively). Stand aboveground net primary production (ANPP) generally increased with increasing site quality, due to increased stand foliage biomass in the early stage, and mainly due to increased growth efficiency in the late stages of stand development. More intensive silvicultural treatments increased foliage biomass, thus increased ANPP at early ages; thereafter silvicultural intensity did not affect foliage biomass, ANPP, and growth efficiency. The trend of early age increases in both foliage biomass and ANPP resulting from increased planting density did not hold true with stand development.
Keywords: pine plantation; maximum stand density index; maximum stand basal area; maximum response; intensive management
ID: 3606017 |
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