Converting Tree Diameter Measured at Root Collar to Diameter at Breast Height

Chojnacky, David C.; Rogers, Paul C.

doi:10.1093/wjaf/14.1.14

Cited by 21 publications

(14 citation statements)

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“…Canopy fuel load was estimated with allometric equations for foliage and fine twigs of ponderosa pine (Fulé et al 2001), Gambel oak (Clary & Tiedemann 1987), pinyon and juniper (Grier et al 1992), Douglas‐fir (Gower et al 1992), and white fir, Engelmann spruce, and aspen (Ter‐Mikaelian & Korzuhkin 1997). We calculated diameter at root collar for pinyon, juniper, and Gambel oak (Chojnacky 1999). We estimated canopy volume by the averages of tree height (top of the canopy) and crown base height (bottom of the canopy).…”

Section: Methodsmentioning

confidence: 99%

“Minimal‐Impact” Restoration Treatments Have Limited Effects on Forest Structure and Fuels at Grand Canyon, USA

Fulé

Covington

Stoddard

et al. 2006

Restoration Ecology

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Restoration treatments were tested on the South Rim (ponderosa pine) and North Rim (mixed conifer) of Grand Canyon National Park, never-harvested forests where the historically frequent surface regime was interrupted in the late 19th century. Treatments were designed for ''minimal impact'' by limiting the size of trees to be thinned and minimizing mechanical equipment. Treatments included (1) thinning of small trees (diameter • 12.7 cm) and prescribed fire; (2) thinning of small trees located close to large old trees and prescribed fire; (3) prescribed fire only; and (4) control. On the South Rim, density declined by 23-45% but basal area only by 9-14%. On the North Rim, density was reduced 32-68% and basal area declined 18-31%. Declines of 5-8% were observed in these same variables in the controls. Surface fuels were significantly reduced in all burned treatments (70-84% reduction in forest floor, 66-76% reduction in woody debris). However, canopy cover was nearly unchanged, and canopy fuel loads were not significantly reduced, although canopy base heights increased. The experiment accomplished the goal of minimally impacting the forest ecosystem but the effects of small-tree thinning plus burning were nearly indistinguishable from those of burning alone. All the treated units were left with modest gain in resistance to severe wildfires but in conditions still far removed from prefire-exclusion conditions.

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Section: Methodsmentioning

confidence: 99%

“Minimal‐Impact” Restoration Treatments Have Limited Effects on Forest Structure and Fuels at Grand Canyon, USA

Fulé

Covington

Stoddard

et al. 2006

Restoration Ecology

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“…Eq. 5 is from Jenkins et al (2003) for the "woodland" class using the recommended conversion from DRC to diameter at breast height (DBH) after Chojnacky and Rogers (1999)…”

Section: Discussionmentioning

confidence: 99%

“…The DRC was defined as the lowest primary branching point for a single stem, where a stem either intersected with a main bole or with the ground (Grier et al, 1992;Chojnacky and Rogers, 1999;Krofcheck et al, 2016). DRC Wet was measured in the field for all disks >5 cm using a thin-line diameter tape and for all disks <5 cm using the mean of two measurements about the major and minor axes using a digital caliper.…”

Section: Basal and Sapwood Areamentioning

confidence: 99%

“…CA is therefore more readily FIGURE 2 | Comparisons between allometric models for predicting aboveground biomass (AGB). (C) considers equivalent stem diameter (ESD) as the predictor using the power models fitted to our observations [solid lines, from panel (A)] and published models (dashed lines, after Grier et al, 1992;Jenkins et al, 2003;Chojnacky et al, 2014, including both the single-stem and multi-stem versions of the DRC-DBH conversion after Chojnacky and Rogers, 1999). (B) considers canopy area as the predictor; the solid lines are the linear models fitted to CA 1 and CA 2 [from Figure 1B] and the dashed lines are linear models reported for Juniperus occidentalis and Juniperus pinchotii (Ansley et al, 2012) and fitted to observations of Juniperus osteosperma (Miller et al, 1981).…”

Section: Prediction Of Aboveground Biomassmentioning

confidence: 99%

“…The multi-stem form makes breast-height (1.3 m above ground level) diameter difficult to apply to most Juniperus species. Consequently, the diameter at root collar (DRC) is commonly used, with the equivalent stem diameter (ESD) for each tree computed as the sum of all stems measured near ground level (Chojnacky and Rogers, 1999;Chojnacky et al, 2014;Krofcheck et al, 2016). Yet DRC is still time-consuming to measure in the field, thus, there is a need for other forms of allometry that can be applied accurately and preferably inexpensively over larger spatial extents (Strand et al, 2008;Hulet et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Allometric Relationships for Predicting Aboveground Biomass and Sapwood Area of Oneseed Juniper (Juniperus monosperma) Trees

et al. 2020

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Across the semiarid ecosystems of the southwestern USA, there has been widespread encroachment of woody shrubs and trees including Juniperus species into former grasslands. Quantifying vegetation biomass in such ecosystems is important because semiarid ecosystems are thought to play an important role in the global land carbon (C) sink, and changes in plant biomass also have implications for primary consumers and potential bioenergy feedstock. Oneseed juniper (Juniperus monosperma) is common in desert grasslands and pinyon-juniper rangelands across the intermountain region of southwestern North America; however, there is limited information about the aboveground biomass (AGB) and sapwood area (SWA) for this species, causing uncertainties in estimates of C stock and transpiration fluxes. In this study, we report on canopy area (CA), stem diameter, maximum height, and biomass measurements from J. monosperma trees sampled from central New Mexico. Dry biomass ranged between 0.4 kg and 625 kg, and cross-sectional SWA was measured on n = 200 stems using image analysis. We found a strong linear relationship between CA and AGB (r 2 = 0.96), with a similar slope to that observed in other juniper species, suggesting that this readily measured attribute is well suited for upscaling studies. There was a 9% bias between different approaches to measuring CA, indicating care should be taken to account for these differences to avoid systematic biases. We found equivalent stem diameter (ESD) was a strong predictor of biomass, but that existing allometric models underpredicted biomass in larger trees. We found SWA could be predicted from individual stem diameter with a power relationship, and that tree-level SWA should be estimated by summing the SWA predictions from individual stems rather than ESD. Our improved allometric models for J. monosperma support more accurate and robust measurements of C storage and transpiration fluxes in Juniperus-dominated ecosystems.

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Positive long‐term impacts of restoration on soils in an experimental urban forest

Ward

Doroski

Felson

et al. 2021

Ecological Applications

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As urbanization increases worldwide, investments in nature‐based solutions that aim to mitigate urban stressors and counter the impacts of global climate change are also on the rise. Tree planting on degraded urban lands—or afforestation—is one form of nature‐based solution that has been increasingly implemented in cities around the world. The benefits of afforestation are, however, contingent on the capacity of soils to support the growth of planted trees, which poses a challenge in some urban settings where unfavorable soil conditions limit tree performance. Soil‐focused site treatments could help urban areas overcome impediments to afforestation, yet few studies have examined the long‐term (>5 yr) effects of site treatments on soils and other management objectives. We analyzed the impacts of compost amendments, interplanting with shrubs, and tree species composition (six species vs. two species) on soil conditions and associated tree growth in 54 experimental afforestation plots in New York City, USA. We compared baseline soil conditions to conditions after 6 yr and examined changes in the treatment effects from 1 to 6 yr. Site treatments and tree planting increased soil microbial biomass, water holding capacity, and total carbon and nitrogen, and reduced soil pH and bulk density relative to baseline conditions. These changes were most pronounced in compost‐amended plots, and the effects of the shrub and species composition treatments were minimal. In fact, compost was key to sustaining long‐term changes in soil carbon stocks, which increased by 17% in compost‐amended plots but declined in unamended plots. Plots amended with compost also had 59% more nitrogen than unamended plots, which was associated with a 20% increase in the basal area of planted trees. Improvements in soil conditions after 6 yr departed from the initial trends observed after 1 yr, highlighting the importance of longer‐term studies to quantify restoration success. Altogether, our results show that site treatments and tree planting can have long‐lasting impacts on soil conditions and that these changes can support multiple urban land management objectives.

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Converting Tree Diameter Measured at Root Collar to Diameter at Breast Height

Cited by 21 publications

References 0 publications

“Minimal‐Impact” Restoration Treatments Have Limited Effects on Forest Structure and Fuels at Grand Canyon, USA

“Minimal‐Impact” Restoration Treatments Have Limited Effects on Forest Structure and Fuels at Grand Canyon, USA

Allometric Relationships for Predicting Aboveground Biomass and Sapwood Area of Oneseed Juniper (Juniperus monosperma) Trees

Positive long‐term impacts of restoration on soils in an experimental urban forest

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