scholarly journals Long‐term fuel and understorey vegetation response to fuel treatments in oak and chaparral stands of northern California

2020 ◽  
Author(s):  
Caroline A. Martorano ◽  
Jeffrey M. Kane ◽  
Eamon A. Engber ◽  
Jennifer Gibson
Keyword(s):  
Northern California ◽  
Vegetation Response ◽  
Fuel Treatments ◽  
Understorey Vegetation

scholarly journals Short- and long-term effects of ponderosa pine fuel treatments intersected by the Egley Fire Complex, Oregon, USA

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Jessie M. Dodge ◽  
Eva K. Strand ◽  
Andrew T. Hudak ◽  
Benjamin C. Bright ◽  
Darcy H. Hammond ◽  
...  
Keyword(s):  
Prescribed Fire ◽  
Vegetation Cover ◽  
Tree Density ◽  
Tree Canopy ◽  
Fuel Treatments ◽  
Dead Tree ◽  
High Severity ◽  
Short And Long Term ◽  
One Year

Abstract Background Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007 Egley Fire Complex in Oregon, USA. We also assessed short- and long-term fuel treatment impacts on field-measured attributes one and nine years post fire. Results One-year post-fire burn severity (dNBR) was lower in treated than in untreated sites across the Egley Fire Complex. Annual NBR trends showed that treated sites nearly recovered to pre-fire values four years post fire, while untreated sites had a slower recovery rate. Time since treatment and dNBR significantly predicted tree canopy and understory green vegetation cover in 2008, suggesting that tree canopy and understory vegetation cover increased in areas that were treated recently pre fire. Live tree density was more affected by severity than by pre-fire treatment in either year, as was dead tree density one year post fire. In 2008, neither treatment nor severity affected percent cover of functional groups (shrub, graminoid, forb, invasive, and moss–lichen–fungi); however, by 2016, shrub, graminoid, forb, and invasive cover were higher in high-severity burn sites than in low-severity burn sites. Total fuel loads nine years post fire were higher in untreated, high-severity burn sites than any other sites. Tree canopy cover and density of trees, saplings, and seedlings were lower nine years post fire than one year post fire across treatments and severity, whereas live and dead tree basal area, understory surface cover, and fuel loads increased. Conclusions Pre-fire fuel treatments effectively lowered the occurrence of high-severity wildfire, likely due to successful pre-fire tree and sapling density and surface fuels reduction. This study also quantified the changes in vegetation and fuels from one to nine years post fire. We suggest that low-severity wildfire can meet prescribed fire management objectives of lowering surface fuel accumulations while not increasing overstory tree mortality.

A 10-Year Evaluation of Prescribed Winter Burns in Uneven-Aged Stands of Pinus-Taeda L and P. Echinata Mill - Woody Understorey Vegetation Response

1993 ◽  
Vol 3 (1) ◽  
pp. 13 ◽  
Author(s):  
MD Cain
Keyword(s):  
Pinus Taeda ◽  
Prescribed Burning ◽  
Basal Area ◽  
Vegetation Response ◽  
Understorey Vegetation ◽  
Single Tree ◽  
Pine Regeneration ◽  
Single Tree Selection ◽  
Pinus Taeda L

The effects of burning cycles and pine basal area levels were assessed on natural pine regeneration and hardwood development in uneven-aged stands of loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.). The treatments included an unburned control and prescribed winter burns at 3-, 6-, and 9-yr intervals. Basal area treatments were 9, 14, 18, and 23 m2 ha-1 for the merchantable-pine component and were maintained on a 6-yr cutting cycle using single-tree selection. Ten years after the study was initiated, density and quadrat stocking of pine regeneration were negatively correlated with overstorey basal area. The 6-yr burning cycle had higher pine density and better quadrat stocking of pine regeneration compared with any other bum treatment mainly because the 6-yr burning cycle coincided with a bumper pine seedcrop and the 6-yr cutting cycle. Recurring fires tended to result in reduced size of hardwood competition but had less impact on hardwood density. When considering a prescribed burning program in uneven-aged stands of loblolly and shortleaf pines, more attention should be given to density, quadrat stocking, and size of established pine regeneration and to expected seedcrops rather than to the prosecution of rigid burning schedules.

scholarly journals Long-term vegetation response following post-fire straw mulching

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Jonathan D. Bontrager ◽  
Penelope Morgan ◽  
Andrew T. Hudak ◽  
Peter R. Robichaud
Keyword(s):  
Vegetation Response ◽  
Straw Mulching

Catastrophic disturbances in headwater streams: the long-term ecological effects of debris flows and debris floods in the Klamath Mountains, northern California

2010 ◽  
Vol 67 (10) ◽  
pp. 1596-1610 ◽  
Author(s):  
Matthew R. Cover ◽  
Juan A. de la Fuente ◽  
Vincent H. Resh
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Headwater Streams ◽  
Ecological Effects ◽  
Ecosystem Structure ◽  
Northern California ◽  
Klamath Mountains ◽  
Mountainous Landscapes ◽  
Debris Floods

Debris flows and debris floods are catastrophic disturbances in steep, mountainous landscapes throughout the world, but little is known about the long-term ecological effects of these events on headwater streams. In 10 basins (10–20 km2) in the Klamath Mountains, northern California, USA, we used a space-for-time substitution to infer the long-term (10–100 years) effects of debris flows on stream ecosystem structure. Debris flows mobilized sediment and wood and removed riparian vegetation from large portions of channel networks. Stream temperatures were significantly warmer in streams that had recent debris flows (<10 years ago). Large wood, benthic organic matter, and detritivorous stoneflies were all very sparse in recent debris flow streams, suggesting that allochthonous energy pathways took decades to recover. Rainbow trout ( Oncorhynchus mykiss ) were abundant in recent debris flow streams, but populations of other vertebrates such as coastal giant salamander ( Dicamptodon tenebrosus ) and coastal tailed frog ( Ascaphus truei ) were virtually absent. Increased frequencies of catastrophic debris flows associated with forest management practices can have significant negative impacts on aquatic biodiversity in forested, mountainous landscapes.

What state of the world are we in? Targeted monitoring to detect transitions in vegetation restoration projects.

2021 ◽  
Author(s):  
Christopher Jones ◽  
Freya Thomas ◽  
Damian Michael ◽  
Hannah Fraser ◽  
Elliot Gould ◽  
...  
Keyword(s):  
Best Practice ◽  
Monitoring Program ◽  
Vegetation Restoration ◽  
Understorey Vegetation ◽  
Vegetation Condition ◽  
Monitoring Strategies ◽  
State And Transition Model ◽  
Condition State

Monitoring vegetation restoration is challenging because ‘best practice’ monitoring is costly, requires long-term funding, and involves monitoring multiple vegetation variables which are often not linked back to learning about progress toward objectives. There is a clear need for the development of targeted monitoring programs that focus on a reduced set of variables that are tied to specific restoration objectives. In this paper, we present a method to progress the development of a targeted monitoring program, using a pre-existing state-and-transition model. We i) use field data to validate an expert-derived classification of woodland condition states; ii) use this data to identify which variable(s) help differentiate woodland condition states; and iii) identify the target threshold (for the variable) that signifies the desired transition has been achieved. The measured vegetation variables from each site in this study were good predictors of the different states of vegetation condition. We show that by measuring only a few of these variables, it is possible to assign the vegetation condition state for a collection of sites, and monitor if and when a transition to another state has occurred. Out of nine vegetation variables considered, the density of immature trees and percentage of exotic understorey vegetation cover were the variables most frequently specified as effective to define a threshold or transition. We synthesise findings by presenting a decision tree that provides practical guidance for the development of targeted monitoring strategies for woodland vegetation.

Mitigation of drought stress in forest stands - insights from a throughfall-exclusion and a thinning experiment

2020 ◽  
Author(s):  
Timo Gebhardt ◽  
Benjamin D. Hesse ◽  
Thorsten E.E. Grams ◽  
Christian Ammer ◽  
Karl-Heinz Häberle
Keyword(s):  
Drought Stress ◽  
Forest Management ◽  
Soil Water ◽  
Norway Spruce ◽  
Intraspecific Competition ◽  
Basal Area ◽  
Understorey Vegetation ◽  
Management Measures ◽  
Throughfall Exclusion

&lt;p&gt;Due to climate change suitable forest management measures are required to mitigate the proposed exacerbating drought events as already observed in central Europe in summer 2003, 2015, 2018, and 2019. This contribution summarizes the findings of two long-term field experiments studying different forest management measures aiming at mitigating drought in forest stands.&lt;/p&gt;&lt;p&gt;The first study investigated the potential of mixing tree composition for mitigating drought stress in Norway spruce (Picea abies [L.] Karst.). To this end, a five-year study with repeated summer droughts, experimentally induced via throughfall-exclusion (TE), was performed. The study objects were mature (60-80 years) old stands of Norway spruce in monoculture and mixture with European beech (Fagus sylvatica (L.). The impacts of repeated summer droughts were assessed on about 100 trees distributed on 12 plots and accessible via canopy crane (Kranzberg forest ROOF experiment in southern Germany). Predawn leaf water potentials of Norway spruce reached minima of -1.8 MPa, but were not affected by species mixture. Nevertheless, daily xylem sapflow density was increased up to 40% in mixture compared to pure strands. Likewise, stem growth, i.e. relative basal area increment, showed significantly higher drought resistance in mixture compared to monocultures.&lt;/p&gt;&lt;p&gt;While altering forest stand composition seems to be promising on the long-term, the conversion from monocultures is often economically not suitable for young stands in the short- to medium-term. Therefore, reducing intraspecific competition via thinning is a frequently discussed option investigated in the second, eight-year-long study. In a 26-year old Norway spruce monoculture, three thinning intensities, i.e. unchanged (control), moderate thinning (MT with reduced basal area by 43%) and heavy thinning (HT, reduced basal area by 67%) were applied, potentially mitigating drought by reducing intraspecific competition and increasing soil water availability. Indeed, in both thinning intensities the duration of drought stress for the trees (soil water content below critical value) was reduced compared to controls for up to 5-7 years following the event. However, increased radiation and higher growth rates of the individual trees accompanied by the fast establishment of a vital ground vegetation diminished the difference in stand transpiration between MT and HT within two years. Moreover, belowground competition with the understorey vegetation suppressed fine root recovery under HT compared to MT in contradiction to increased leaf area on HT on tree-level and therefore increased transpirational demand.&lt;/p&gt;&lt;p&gt;The presented studies suggest admixing of broadleaved beech into monocultures of Norway spruce to be a promising management measure in the long-term. In juvenile monocultures of Norway spruce frequent and intense thinning interventions while preventing the establishment of a vital understorey vegetation appears to be a promising forest measure, mitigating drought without losing sight of economic needs.&lt;/p&gt;

Changes in forest understorey vegetation in Norway related to long-term soil acidification and climatic change

2004 ◽  
Vol 15 (4) ◽  
pp. 437-448 ◽  
Author(s):  
Tonje Økland ◽  
Vegar Bakkestuen ◽  
Rune Halvorsen Økland ◽  
Odd Eilertsen
Keyword(s):  
Climatic Change ◽  
Soil Acidification ◽  
Understorey Vegetation ◽  
Forest Understorey
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