Abstract
Assessment of aboveground biomass stocks in the coniferous forests of the inland northwest USA is important for timber, bioenergy, and carbon inventories, as well as for wildfire risk determination. In this study, individual tree biomass equation systems are developed for 7 regionally important conifer species using data from 470 felled trees sampled across 84 stands and spanning a range of diameters at breast height (1.37 m; dbh) running from 5 cm to 105 cm. The equation systems permit estimation of crown biomass components (i.e., foliage, dead branches, and live branches by size class) and stem components (abovestump stemwood and stembark), as well as compatible estimates of (sub)totals. The systems draw on commonly collected inventory variables including dbh, tree height, and live crown length. All biomass components scaled approximately linearly with dbh on the logarithmic scale, but equation systems drawing on both dbh and height provided more accurate estimates for all species; systems drawing additionally on live crown length provided more accurate estimates still for all species but one. In line with previous work, incorporation of live crown length improved live crown component equations most, but also improved stem component equations for two species. Across species and systems, stem components and subtotals were most accurately estimated (mean absolute errors ∼10%) while dead branch biomass estimation proved least tractable (mean absolute errors >50%). Overall, the reported biomass equation systems draw on the largest felled tree samples collected from the region, and provide the most comprehensive basis developed to date for regional forest biomass assessments over the inland northwest.
| Original language | English |
|---|---|
| Pages (from-to) | 179-188 |
| Number of pages | 10 |
| Journal | Forest Ecology and Management |
| Volume | 432 |
| DOIs | |
| State | Published - Jan 15 2019 |
Funding
This research was motivated and initiated by the Inland Northwest Growth & Yield (INGY) Cooperative and its then director John G. Goodburn. The field work would not have been possible without the cooperation of private, state, federal, and tribal land managers across the inland northwest, nor without the efforts of a tireless regiment of graduate students and technicians. Funding for the research was provided by the Spokane Tribe of Indians, INGY, the US Forest Service Northern Region, the Joint Fire Sciences Program ( 10-1-02-13 ), and the US Forest Service Forest Inventory & Analysis program ( 11-JV-11242305-120 ; 16-JV-11221638-127 ).
| Funders | Funder number |
|---|---|
| 10-1-02-13 | |
| U.S. Forest Service-Retired | 11-JV-11242305-120, 16-JV-11221638-127 |
Keywords
- Forest inventory
- Inland northwest
- Randomized branch sampling
- Tree biomass equation systems
