{"title":"Characterisation of harvest residues on New Zealand’s steepland plantation cutovers","authors":"Campbell Harvey, R. Visser","doi":"10.33494/nzjfs522022x174x","DOIUrl":null,"url":null,"abstract":"Background: Timber harvesting in New Zealand’s plantation forests results in relatively large volumes of woody residues being generated. While a proportion of these residues are concentrated at the landings where the trees are processed, the majority of residues are distributed throughout the cutover. Harvest residues present a biomass market opportunity, however managing un-merchantable residues remains essential as the material can present a mass mobilisation risk. Quantifying cutover residues in terms of volume provides an important step for marketing and for improving post-harvest management.\nMethods: A refined Line Intersect Sampling (LIS) method was used to measure the cutover residues at 17 recently harvested steepland sites. These covered a range of whole tree harvesting systems, silviculture and geographical locations. The harvesting sites varied in size from 2.3 to 41.1 ha, with an average of 11x 60 m LIS transect plots completed at each site. Woody harvest residues >25 mm in diameter were measured.\nResults: The median volume of woody residues was 88 m3/ha, ranging from 0 m3/ha in an area swept bare, up to 580 m3/ha in an area severely impacted by windthrow prior to harvest. A distribution of volumes by plot showed a positive skew with an interquartile range of 87 m3/ha. Timber that was considered merchantable as a log at the time of harvest, being >10 cm in small end diameter and >4 m in length, accounted for a median of 11 m3/ha. Residues >10 cm in small end diameter and >80 cm in length that could make a viable biomass product, described as ‘binwood’, accounted for a further 19 m3/ha at the median. Cutovers harvested with cable-based systems had greater median total residue volumes than those harvested with ground-based systems (110 m3/ha versus 68 m3/ha) however the felling method employed made no significant difference to total residue volumes.\nConclusions: This study provides cutover residue measurements that can be used to improve post-harvest management, as both a substantial opportunity for improved crop utilisation and also for reducing mobilisation risk. It also provides a contemporary benchmark against which to measure change as harvesting technology or methodology develops.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Zealand Journal of Forestry Science","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.33494/nzjfs522022x174x","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 2
Abstract
Background: Timber harvesting in New Zealand’s plantation forests results in relatively large volumes of woody residues being generated. While a proportion of these residues are concentrated at the landings where the trees are processed, the majority of residues are distributed throughout the cutover. Harvest residues present a biomass market opportunity, however managing un-merchantable residues remains essential as the material can present a mass mobilisation risk. Quantifying cutover residues in terms of volume provides an important step for marketing and for improving post-harvest management.
Methods: A refined Line Intersect Sampling (LIS) method was used to measure the cutover residues at 17 recently harvested steepland sites. These covered a range of whole tree harvesting systems, silviculture and geographical locations. The harvesting sites varied in size from 2.3 to 41.1 ha, with an average of 11x 60 m LIS transect plots completed at each site. Woody harvest residues >25 mm in diameter were measured.
Results: The median volume of woody residues was 88 m3/ha, ranging from 0 m3/ha in an area swept bare, up to 580 m3/ha in an area severely impacted by windthrow prior to harvest. A distribution of volumes by plot showed a positive skew with an interquartile range of 87 m3/ha. Timber that was considered merchantable as a log at the time of harvest, being >10 cm in small end diameter and >4 m in length, accounted for a median of 11 m3/ha. Residues >10 cm in small end diameter and >80 cm in length that could make a viable biomass product, described as ‘binwood’, accounted for a further 19 m3/ha at the median. Cutovers harvested with cable-based systems had greater median total residue volumes than those harvested with ground-based systems (110 m3/ha versus 68 m3/ha) however the felling method employed made no significant difference to total residue volumes.
Conclusions: This study provides cutover residue measurements that can be used to improve post-harvest management, as both a substantial opportunity for improved crop utilisation and also for reducing mobilisation risk. It also provides a contemporary benchmark against which to measure change as harvesting technology or methodology develops.
期刊介绍:
The New Zealand Journal of Forestry Science is an international journal covering the breadth of forestry science. Planted forests are a particular focus but manuscripts on a wide range of forestry topics will also be considered. The journal''s scope covers forestry species, which are those capable of reaching at least five metres in height at maturity in the place they are located, but not grown or managed primarily for fruit or nut production.