•Mechanical pruning can delay, even eradicate, the impact of Arceuthobium douglasii.•Eradication is more probable in lightly infected trees without infected cohorts.•Perform evaluations to confirm ...eradication no sooner than 14years post-pruning.•Foliage from witches brooms contribute little to long-term tree vitality.
Mid- to very large-sized Douglas-fir (Pseudotsuga menzieseii var. menziesii) that were lightly- to moderately-infected by dwarf mistletoe (Arceuthobium douglasii) were analyzed over a 14-year period to evaluate whether mechanical pruning could eradicate mistletoe (or at least delay the onset of severe infection) without significantly affecting tree vitality and by inference, longevity. Immediate and long-term pruning effects on mistletoe infection severity were assessed by comparing pruned trees (n=173) to unpruned trees (n=55) with respect to: (1) percentage of trees with no visible infections 14years post-pruning, (2) Broom Volume Rating (BVR), and (3) rate of BVR increase 14years post-pruning. Vitality/longevity (compared with unpruned trees) was assessed using six indicators: (1) tree survival, (2) the development of severe infections, (3) the development of dead tops, (4) tree-ring width indices, (5) Normalized Difference Vegetation Index (NDVI) from high-resolution multi-spectral imagery, and (6) live-crown ratio (LCR) and increment. Twenty-four percent of the pruned trees remained free of mistletoe 14years post-pruning. Pruning is most likely to successfully eradicate mistletoe in lightly infected trees (BVR 1 or 2) without infected neighbors. Pruning significantly decreased mean BVR in the pruned versus the unpruned trees. However, the subsequent average rate of intensification (1.3–1.5 BVR per decade) was not affected, implying that a single pruning provides ∼14years respite in the progression of infection levels. Post-pruning infection intensification was slower on dominant and co-dominants than on intermediate or suppressed trees. The success of mistletoe eradication via pruning and need for follow-up pruning should be evaluated no sooner than 14years after pruning to allow for the development of detectable brooms. Based on six indicators, foliage from witches brooms contribute little to long-term tree vitality since removal appears to have little effect on resources available for tree growth and maintenance. In the severely pruned trees, tree-ring width was reduced for several years post-pruning, but then compensated with larger ring width in later years. Both NDVI and LCR increment were significantly higher for the pruned trees than the control trees, while the development of severe infections and/or dead tops was significantly (5× and 3×) higher for the controls. If possible, multiple indicators of tree vitality should be evaluated. Pruning can be worthwhile even if all the mistletoe is not removed, because mistletoe intensification is delayed. The impact of removing the brooms seems to be minimal, and post-pruning crowns had greater NDVI values.
In 2005, the 10-year effects of two silvicultural treatments (group-selection and shelterwood) on tree-growth loss and mortality caused by Armillaria ostoyae were compared with no treatment in a ...mixed-conifer forest in south-central Oregon. Ten years after treatment, Armillaria-caused mortality varied by species and was greatest in Shasta red fir (38% of trees per acre) and white fir (31%) and much less in Douglas-fir (3%) and ponderosa pine (0%). Ten years after harvesting, leave-tree mortality caused by Armillaria root disease was not significantly different in treated than in the unharvested units, nor was there significant diameter-growth response to the harvesting even in large ponderosa pine and Douglas-fir. The silvicultural treatments did have some benefits: (1) leave-tree mortality appeared, at least, not to be exacerbated by harvesting; (2) more disease-resistant pine, cedar, and larch seedlings and saplings survived in the shelterwood-harvest stands and group-selection openings than in comparable areas that were not harvested; and (3) living wood fiber was recovered from the treated stands, as well as dying and dead fuels that could exacerbate wildfire losses. Insights into host-pathogen interactions and recommendations for silvicultural options are presented. This is a case study from a single site and should be interpreted as such.
Natural disturbances including wildfire, insects and disease are a growing threat to the remaining late successional forests in the Pacific Northwest, USA. These forests are a cornerstone of the ...region's ecological diversity and provide essential habitat to a number of rare terrestrial and aquatic species including the endangered northern spotted owl (
Strix occidentalis caurina). Wildfires in particular have reduced the amount of late successional forests over the past decade, prompting land managers to expand investments in forest management in an attempt to slow losses and mitigate wildfire risk. Much of the emphasis is focused specifically on late successional reserves established under the Northwest Forest Plan to provide habitat for spotted owls. In this paper, we demonstrate a probabilistic risk analysis system for quantifying wildfire threats to spotted owl habitat and comparing the efficacy of fuel treatment scenarios. We used wildfire simulation methods to calculate spatially explicit probabilities of habitat loss for fuel treatment scenarios on a 70,245
ha study area in Central Oregon, USA. We simulated 1000 wildfires with randomly located ignitions and weather conditions that replicated a recent large fire within the study area. A flame length threshold for each spotted owl habitat stand was determined using the forest vegetation simulator and used to predict the proportion of fires that resulted in habitat loss. Wildfire modeling revealed a strong spatial pattern in burn probability created by natural fuel breaks (lakes and lava flows). We observed a non-linear decrease in the probability of habitat loss with increasing treatment area. Fuels treatments on a relatively minor percentage of the forested landscape (20%) resulted in a 44% decrease in the probability of spotted owl habitat loss averaged over all habitat stands. The modeling system advances the application of quantitative and probabilistic risk assessment for habitat and species conservation planning.
A 500-ac mixed-conifer forest near Cache Mountain in central Oregon was examined in 1979, 1992, 2002, 2004, and 2005 to document causes of forest health decline and subsequent wildfire damage. The ...site is dominated by grand fir (Abies grandis) and ponderosa pine (Pinus ponderosa), with some lodgepole pine (Pinus contorta) and subalpine fir (Abies lasiocarpa). Part of the area was clearcut or shelterwood harvested from 1983 to 1985. Between 1979 and 1992, grand fir increased substantially, whereas ponderosa pine decreased in stems and basal area/ac in the unharvested areas. From 1979 to 2002, grand fir experienced severe mortality that was caused primarily by the root pathogen, Armillaria ostoyae, and the fir engraver (Scolytus ventralis). In 2003, a wildfire burned all of the study area, and by 2004, most of the grand fir, subalpine fir, and lodgepole pine was killed. The least amount of mortality from fire occurred in the larger-diameter ponderosa pine. Two years after the 2003 fire, some of the grand firs with bole or crown scorch that were alive in 2004 were killed by fir engravers by 2005. For ponderosa pines, only a few trees with bole or crown scorch that were alive in 2004 were killed by bark beetles, mostly mountain pine beetle (Dendroctonus ponderosae) and red turpentine beetle (Dendroctonus valens), by 2005. This case study has relevance to current interpretations of forest health in similar mixed-conifer forests, the major causes of forest health decline, and the role of fire in forest health.
Pruning high-value Douglas-fir can reduce dwarf mistletoe severity and increase longevity in Central Oregon Maffei, Helen M; Gregory M. FilipauthorUSDA Forest Service, Pacific Northwest Regional Office, 1220 SW Third Ave, Portland, OR 97204-2825, United States; Nancy E. GrulkeauthorUSDA Forest Service, Western Wildland Environmental Threat Assessment Center, 3160 NE 3rd Street, Prineville, OR 97754-8119, United States ...
2015
Journal Article
Dwarf mistletoe (Arceuthobium vaginatum subsp. cryptopodum (Engelm.) Hawksworth and Wiens) infestation results in severe loss of wood volume in the ponderosa pine forests (Pinus ponderosa Laws.) of ...Colorado. In this research equations were developed which describe the relationship between dwarf mistletoe incidence, severity and stand structure. The effect and inter-relationship between inter-tree competition and dwarf mistletoe was also described for irregular, multi-aged stands using growth and mortality of two-inch diameter classes as predetermined response variables. Stand structure had a significant effect (P $<$.05) on the relationship between dwarf mistletoe incidence and severity. The ratio of the percent trees infected to stand dwarf mistletoe rating (DMR) was significantly higher for even-aged stands than for multi-aged stands. A component of total stand basal area was used to describe inter-tree competition. BASL, which is the sum of the basal area of the trees in a given size class plus basal area of all trees of larger d.b.h., was a useful predictor of competition for small trees (d.b.h. $\leq$ 10 in.) but not for larger trees (d.b.h. $>$ 10 in.). For larger trees, stand basal area (BA) was a statistically significant (P $<$.05), but weak, predictor of competition. For small trees, BA was significant but not as good a predictor as BASL. Growth of trees of all sizes decreased steadily (beginning when trees were moderately infected) to 50% (at the heaviest infection levels) of the expected growth for uninfected trees. Percent of trees in a d.b.h. class heavily infected with dwarf mistletoe was positively correlated with 10 year mortality rates. For infected trees with d.b.h. $<$ 10 in., competition and d.b.h. were also useful predictors of mortality. A higher level of intertree competition (BASL) resulted in higher mortality rates while mortality declined exponentially with increasing tree d.b.h. The results show that stand density and structure interact together to impact growth and mortality.
Oromotor functioning plays a foundational role in spoken communication and feeding, two areas of significant difficulty for many autistic individuals. However, despite years of research and ...established differences in gross and fine motor skills in this population, there is currently no clear consensus regarding the presence or nature of oral motor control deficits in autistic individuals. In this scoping review, we summarize research published between 1994 and 2022 to answer the following research questions: (1) What methods have been used to investigate oromotor functioning in autistic individuals? (2) Which oromotor behaviors have been investigated in this population? and (3) What conclusions can be drawn regarding oromotor skills in this population? Seven online databases were searched resulting in 107 studies meeting our inclusion criteria. Included studies varied widely in sample characteristics, behaviors analyzed, and research methodology. The large majority (81%) of included studies report a significant oromotor abnormality related to speech production, nonspeech oromotor skills, or feeding within a sample of autistic individuals based on age norms or in comparison to a control group. We examine these findings to identify trends, address methodological aspects hindering cross‐study synthesis and generalization, and provide suggestions for future research.
Lay Summary
Autistic individuals demonstrate movement abnormalities during tasks including walking, balancing, reaching, and tool use. However, little is known about movements of the mouth despite well‐known difficulties with speech and feeding in ASD. Here we (1) summarize studies related to mouth movements in ASD, showing that 81% of these studies indicate significant abnormalities in autistic individuals, (2) discuss common findings in these studies, and (3) make suggestions for future research.
Motor deficits are widely documented among autistic individuals, and speech characteristics consistent with a motor speech disorder have been reported in prior literature. We conducted an ...auditory-perceptual analysis of speech production skills in low and minimally verbal autistic individuals as a step toward clarifying the nature of speech production impairments in this population and the potential link between oromotor functioning and language development.
Fifty-four low or minimally verbal autistic individuals aged 4-18 years were video-recorded performing nonspeech oromotor tasks and producing phonemes, syllables, and words in imitation. Three trained speech-language pathologists provided auditory perceptual ratings of 11 speech features reflecting speech subsystem performance and overall speech production ability. The presence, attributes, and severity of signs of oromotor dysfunction were analyzed, as were relative performance on nonspeech and speech tasks and correlations between perceptual speech features and language skills.
Our findings provide evidence of a motor speech disorder in this population, characterized by perceptual speech features including reduced intelligibility, decreased consonant and vowel precision, and impairments of speech coordination and consistency. Speech deficits were more associated with articulation than with other speech subsystems. Speech production was more impaired than nonspeech oromotor abilities in a subgroup of the sample. Oromotor deficits were significantly associated with expressive and receptive language skills. Findings are interpreted in the context of known characteristics of the pediatric motor speech disorders childhood apraxia of speech and childhood dysarthria. These results, if replicated in future studies, have significant potential to improve the early detection of language impairments, inform the development of speech and language interventions, and aid in the identification of neurobiological mechanisms influencing communication development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The purpose of this paper was to review best-practice methods of collecting and analyzing speech production data from minimally verbal autistic speakers. Data on speech production data in minimally ...verbal individuals are valuable for a variety of purposes, including phenotyping, clinical assessment, and treatment monitoring. Both perceptual ("by ear") and acoustic analyses of speech can reveal subtle improvements as a result of therapy that may not be apparent when correct/incorrect judgments are used. Key considerations for collecting and analyzing speech production data from this population are reviewed. The definition of "minimally verbal" that is chosen will vary depending on the specific hypotheses investigated, as will the stimuli to be collected and the task(s) used to elicit them. Perceptual judgments are ecologically valid but subject to known sources of bias; therefore, training and reliability procedures for perceptual analyses are addressed, including guidelines on how to select vocalizations for inclusion or exclusion. Factors to consider when recording and acoustically analyzing speech are also briefly discussed. In summary, the tasks, stimuli, training methods, analysis type(s), and level of detail that yield the most reliable data to answer the question should be selected. It is possible to obtain rich high-quality data even from speakers with very little speech output. This information is useful not only for research but also for clinical decision-making and progress monitoring.
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