Ice Storm Disturbance Research Articles

Responses at the stand and tree level to ice storm injuries in beech forests in eastern Serbia

The paper presents the study on the condition and structural stability of European beech (Fagus sylvatica L.) stands after the 2014 ice storm disturbance. The research was conducted in three pure beech stands on the Rtanj mountain in eastern Serbia. The stand condition after the ice storm was analyzed using changes in taxation elements. The assessment of tree damage was done according to the ICP Forests methodology, while the structural stability of the stands and individual trees was analyzed using the slenderness coefficient. The obtained results indicate very heterogeneous responses of beech stands to the negative impact of the ice storm. Heterogeneity is not only expressed between stands but also within individual stands. The stands after the ice storm are characterized by significantly reduced values of production indicators, but also by satisfactory stability, considering that the trees from the understory suffered the most. Statistically significant differences in the stability of trees of different dimensions expressed through the slenderness coefficient were determined. Consequently, the stands have maintained an appropriate level of stability thanks to the survival and resistance of the dominant trees that are the bearers of functions in these stands (trees with dbh > 40 cm). This indicates the great potential of silvicultural treatments that can increase the stability and resistance of stands in areas with a high risk of such phenomena. In addition, repressive action in the form of salvage logging has a very important role with the aim of ensuring the continuity of stands after damage has occurred.

The phylogenetic structure of a subtropical evergreen broad-leaved forest community before and after an ice-snow storm in Gutianshan, eastern China

<p indent=0mm>Ice-snow storms are a major natural disturbance, and it is an important driver of forest regeneration in middle and high latitudes. Previous studies have focused on the impact of ice-snow storm on forest dynamics|however, few studies have investigated the impact of ice-snow storms on the phylogenetic structure of a forest community. In this study, we studied the phylogenetic structure of a 24-ha subtropical evergreen, broad-leaved forest in Gutianshan National Nature Reserve in Zhejiang Province before (2005) and after (2010) an ice-snow storm. We compared NRI and NTI of the community at three grain sizes, four topographic habitat types, and three size classes between before and after the ice-snow storm. Furthermore, we simulated random mortality during 2005–2010 and compared MPD and MNTD between observed values and random mortality in 2010. We found that (1) NRI and NTI were significantly higher after the storm across grain size, habitat, and size class. (2) Additionally, MNTD were not significantly different between random mortality and observed values in 2010 for the three size classes and two habitats, whereas all other cases showed that MNTD and MPD were significantly larger for random mortality than that for observed values. The results indicate that community phylogenetic structures of the study forest were more clustered after the storm, and they were little affected by grain size, vertical layer and habitat condition. This study improves our understanding of ice-storm disturbance on subtropical evergreen broad-leaved forest community phylogenetic structure.

Effects of an experimental ice storm on forest canopy structure

Intermediate disturbances are an important component of many forest disturbance regimes, with effects on canopy structure and related functions that are highly dependent on the nature and intensity of the perturbation. Ice storms are an important disturbance mechanism in temperate forests that often result in moderate-severity, diffuse canopy damage. However, it has not previously been possible to distinguish the specific effect of ice storm intensity (as ice accretion) from predisturbance stand characteristics and physiographic factors. In this study, we utilized a novel experimental ice storm treatment to evaluate the effects of variable ice accretion levels on forest canopy structure. Our results verified significant impacts of ice storm disturbance on near-term canopy structural reorganization. Canopy openness, light transmission, and complexity increased significantly relative to predisturbance baselines and undisturbed controls. We documented variable impacts with disturbance intensity, as significant canopy changes largely occurred with ice accretion levels of ≥12.7 mm. Repeated ice storm disturbance (two consecutive years) had marginal, rather than compounding, effects on forest canopy structure. Our findings are relevant to understanding how ice storms can affect near-term forest canopy structural reorganization and ecosystem processes and add to a growing base of knowledge on the effects of intermediate disturbances on canopy structure.

Forecasting Urban Forest Ecosystem Structure, Function, and Vulnerability

The benefits derived from urban forest ecosystems are garnering increasing attention in ecological research and municipal planning. However, because of their location in heterogeneous and highly-altered urban landscapes, urban forests are vulnerable and commonly suffer disproportionate and varying levels of stress and disturbance. The objective of this study is to assess and analyze the spatial and temporal changes, and potential vulnerability, of the urban forest resource in Toronto, Canada. This research was conducted using a spatially-explicit, indicator-based assessment of vulnerability and i-Tree Forecast modeling of temporal changes in forest structure and function. Nine scenarios were simulated for 45 years and model output was analyzed at the ecosystem and municipal scale. Substantial mismatches in ecological processes between spatial scales were found, which can translate into unanticipated loss of function and social inequities if not accounted for in planning and management. At the municipal scale, the effects of Asian longhorned beetle and ice storm disturbance were far less influential on structure and function than changes in management actions. The strategic goals of removing invasive species and increasing tree planting resulted in a decline in carbon storage and leaf biomass. Introducing vulnerability parameters in the modeling increased the spatial heterogeneity in structure and function while expanding the disparities of resident access to ecosystem services. There was often a variable and uncertain relationship between vulnerability and ecosystem structure and function. Vulnerability assessment and analysis can provide strategic planning initiatives with valuable insight into the processes of structural and functional change resulting from management intervention.

Impacts of the 2008 ice storm on structure and composition of an evergreen broad-leaved forest community in eastern China

Subtropical evergreen broad-leaved forest (EBLF) is the zonal vegetation of the Chinese subtropi- cal region, among which the most typical and widely distributed type is mid-subtropical EBLF. To explore how the 2008 ice-storm affected the short-term dynamics of mid-subtropical EBLF, we examined the com- munity structure and species composition pre and post the ice storm of the 24 ha forest dynamics plot in Gutianshan. We found that although the DBH size class structure was highly consistent pre and post the ice storm, community level recruitment was low and mortality was high. Results of community dynamics analy- ses conducted at various grain size scales implied general depressions, despite the different rates of change between habitats. Species abundance and ABH (area at breast height) both decreased but species frequency and IV (importance value) did not change. Species in abundance, ABH, frequency and IV were highly con- sistent pre and post the ice storm. The results imply that the 2008 ice storm negatively impacted the short-term dynamics of the EBLF community in Gutianshan. The severity of impact was associated with stem DBH and topography. However, the community structure of this old-growth forest showed its consider- able resistance to ice storm disturbance.

Spatial response patterns of subtropical forests to a heavy ice storm: a case study in Poyang Lake Basin, southern China

In early 2008, an unexpected ice storm hits southern China, severely affected the subtropical forest ecosystems. We used the moderate resolution imaging spectroradiometer products of Enhanced Vegetation Index (EVI) corroborated with information gathered from field investigations to analyze the spatial patterns of forest damage in Poyang Lake Basin. The results showed that forests on windward aspects and 400–1,000 m elevation zones are sensitive to ice storm. The spatial pattern of forest damage after the ice storm can be understood in light of topographical sheltering effect. Due to the mountains of the basin blocked the cold flow and wind, the damage on windward aspects showed more severity than other aspects, which was similar like previous studies in North America. The most severe canopy loss beyond 63 % (EVI loss 0.085) occurring on 400–800 m elevation zones. The secondary severe forest damage was on 800–1,500 m elevation zones with canopy loss 33 % (EVI loss 0.035), which unlike previous studies in North American that found damage was rapidly decreased at these elevations. This observation fits the ecological disturbances theory suggests that ice storms generating greater damage in forests which less frequently impacted by ice disturbance events. There appears to be a broader pattern of forest damage associated with ice storm in subtropical forests than in temperate regions. This implies that the subtropical forests are more vulnerable than temperate forests to ice storm disturbance.

Spatial patterns of ice storm disturbance on a forested landscape in the Appalachian Mountains, Virginia

Ice storms (major freezing rain events) periodically disturb forests in eastern North America. The damage may vary spatially, especially in complex terrain. This study uses satellite imagery to investigate spatial heterogeneity of forest damage caused by ice storms that affected the Appalachian Mountains, Virginia during 1994. The results display a region‐scale (southwest‐to‐northeast) gradient in damage that apparently corresponds to a gradient in the depth of ice that accumulated during the storms. Damage also varied topographically, particularly by aspect. Damage was most extensive on east‐, southeast‐ and south‐facing slopes; at middle elevations; and on slopes of moderate steepness.

Analysis of deciduous tree species dynamics after a severe ice storm using SORTIE model simulations

Ice storms are frequent natural disturbance events in hardwood forests of eastern Canada and the United States, but their effects on forest dynamics are not well understood. Our objectives were to characterize short- and long-term tree species dynamics after a severe ice storm, and to assess the influence of spatial distribution of trees on these dynamics. SORTIE, a spatially explicit individual tree-based forest model, was used to simulate the effects of a severe ice storm on 300 years old stands. Crown radius was reduced and tree mortality was increased for a 5-year period following the ice storm disturbance. To investigate the influence of the spatial distribution of trees, we repeated the same experiment in a uniformly distributed stand where we systematically assigned coordinates of all trees, saplings and seedlings before the ice storm was modeled. Our results showed that six types of dynamics can be adopted by a species following an ice storm and that spatial distribution of trees influenced the species responses. In summary, we found that a combination of factors, namely, species density and spatial distribution, shade tolerance, growth rate, extent of canopy openness and canopy loss resulting from the ice storm, determine how tree species respond to ice storm disturbance.

Riparian roots through time, space and disturbance

Riparian zones are landscape features adjacent to streams and are widely recognized as important in reducing erosion and filtering groundwater. Few studies directly investigate rooting dynamics of riparian areas, and little information exists concerning riparian root densities, biomass, depth profiles, changes through time, or vulnerability to disturbance. This study examined spatial and temporal patterns in root systems in streamsides influenced by season, hydrologic regime, vegetative composition, and ice storm disturbance in the eastern Adirondacks, New York. Sequential root cores and in-growth cores were collected from June 2000 through August 2001 in a riparian area with minimal ice storm damage adjacent to a third-order stream. Data were used to assess seasonal trends in root biomass and to provide a reference for spatial comparisons. The biomass and surface area of roots collected in the reference site cores were compared with cores collected at nine additional riparian sites differing in degree of canopy damage from the January 1998 ice storm. Average root biomass at the reference site was 1330 g/m2, comparable to or greater than values reported for terrestrial and other riparian systems. Root biomass varied seasonally with a maximum root biomass in August, 2000; this result was not repeated the following year after the water table inundated much of the rooting zone in mid-June. Root biomass was spatially variable on a range of scales. Although the maximum root surface area occurred in the upper 10 cm, root biomass peaked at 20–30 cm belowground, unlike observations from most other root studies where the maximum root biomass has been found in the top 10 cm. Areas severely damaged by the ice storm had significantly less root biomass and surface area than areas with low damage. This study demonstrates that root biomass in riparian areas is highly dynamic over time, space, and across disturbance sites. Our findings suggest that the spatial variability in root densities has direct implications for riparian vulnerability to erosion.

Short-Term Temperature Response in Forest Floor and Soil to Ice Storm Disturbance in a Northern Hardwood Forest

Abstract Significant changes in the temperature of forest floor and soil of the Hubbard Brook Experimental Forest occurred as a result of canopy damage caused by a major ice storm in Jan. 1998. The summertime patterns among open, brush-pile, and reference sites were clear and repeatable: (1) air temperatures at all sites peaked at about the same time each day although the average open-site values were 1 to 4°C higher; (2) the pattern at 2- and 15-cm [0.8- and 5.9-in.] depths was similar to air; (3) the open value was 5 to 9 and 6 to 10°C higher than that in the reference site and brush-pile sites, respectively; (4) there was a lag of ∼0.3 hours for daily peak temperatures between the air and 2-cm depth, and ∼3.3 hours between the daily maximum temperature at 2- and 15-cm depth for the open sites; (5) the open site temperature at both 2- and 15-cm depth was ∼2°C higher than reference and brush-pile temperatures (average daily temperature for the brush-pile site rose to be roughly equal to that in the open site in Aug. 1999 and Aug. 2000, while the reference site remained about 2°C lower); (6) small, but not statistically significant, changes were observed at the 50-cm [19.7-in.] depth where the open site was ∼1°C higher than the brush-pile or reference sites; and (7) regrowth of vegetation in the canopy gaps during the first 3 years reduced forest floor temperatures to or below the temperature at the 2-cm depth in the reference site. These results have potential ecological importance to the northern hardwood forest ecosystem. North. J. Appl. For. 21(4):209 –219.

Stand dynamics of a yellow-poplar ( Liriodendron tulipifera L.) forest in the Appalachian Mountains, Virginia, USA

Yellow-poplar ( Liriodendron tulipifera L.) is a large, rapidly growing, shade-intolerant tree species common after disturbances on moist sites in the Appalachian Mountains. The species is typically scattered throughout old-growth mesophytic forests, where periodic gap formation creates conditions favorable for yellow-poplar establishment and growth. On abandoned agricultural fields, however, it is common for nearly monospecific forests of yellow-poplar to develop. This study examines stand dynamics of a yellow-poplar forest in western Virginia, USA that was established on agricultural fields abandoned in the late 1940s. Increment cores were collected from yellow-poplar trees growing on exposed ridgetops and in a more sheltered hollow. Tree-ring data show that the forest is even-aged. Tree establishment began about 5 years earlier on the ridgetops than in the hollow. Major ice storms disturbed the forest in 1978 and 1994, with two separate events in 1994. Ice storms disturb forests by depositing heavy loads of freezing rain on trees, breaking or uprooting them. The dendroecological data collected for this study provide little support for the hypothesis that ice storm disturbance promotes the establishment of new yellow-poplar cohorts. However, the data show that radial growth of some trees increased after ice storm disturbance, a pattern that reflects the increased availability of light following disturbance. Radial growth declined in some other trees as a consequence of severe injury during the storms. Radial growth responses following the 1978 ice storm were stronger on the ridgetops than in the hollow, suggesting that tree damage was more severe on the higher, more exposed sites. Growth responses were relatively mild following the storms of 1994, and did not exhibit pronounced topographic variations.

Ice‐storm disturbance and long‐term forest dynamics in the Adirondack Mountains

Ice storms cause periodic disturbance to temperate forests of eastern North America. They are the primary agents of disturbance in some eastern forests. In this paper, a forest gap model is employed to explore consequences of ice storms for the long‐term dynamics of Tsuga canadensis‐northem hardwoods forests. The gap model LINKAGES was modified to simulate periodic ice storm disturbance in the Adirondack Mountains of New York. To adapt the gap model for this purpose, field data on ice storm disturbance are used to develop a polytomous logistic regression model of tree damage. The logistic regression model was then incorporated into the modified forest gap model, LINK ADIR, to determine the type of damage sustained by each simulated tree.The logistic regression model predicts high probabilities of bent boles or severe bole damage (leaning, snapping, or uprooting) in small‐diameter trees, and increasing probability of canopy damage as tree size increases. Canopy damage is most likely on gentle slopes; the probability of severe bole damage increases with increasing slope angle.In the LINKADIR simulations, tree damage type determines the probability of mortality; trees with severe bole damage are assigned the highest mortality rate. LINKADIR predicts Tsuga canadensis dominance in mesophytic old‐growth forests not disturbed by ice storms. When ice storms are simulated, the model predicts Acer saccharum‐dominated forests with higher species richness. These results suggest that ice storms may function as intermediate disturbances that enhance species richness in forested Adirondack landscapes.

Ice-storm disturbance and long-term forest dynamics in the Adirondack Mountains

Ice-storm disturbance and long-term forest dynamics in the Adirondack Mountains

Using dendrochronology to identify major ice storm events in oak forests of southwestern Virginia

Major ice storms are significant forest disturbance agents and natural hazards in east- ern North America. Studies of forest damage suggest that ice storm severity varies among topo- graphic positions, but little climatic information is available to evaluate fine-scale variations in ice storm climatology. Our study assesses the utility of tree-ring analysis for identifying fine-scale spatial patterns and long-term temporal variations in the frequency of major ice storms. We looked for ice storm signals in tree-ring chronologies of chestnut oak Quercus prinus L. and black oak Q. velutina Lam. at 2 sites in southwestern Virginia that were affected by known ice storms in 1979 and 1994. Radial growth of these species exhibits a dual response to ice storm disturbance. Trees with substan- tial canopy loss show reduced radial growth for several years following an ice storm. Other trees dis- play increased growth due to the loss of competitors. We identified thresholds of ring-width increase and decrease that distinguished ice storms from other events, permitting a preliminary attempt to reconstruct ice storm history at each of the 2 study sites. For our Gap Mountain site, ring-width chronologies spanning the period 1914-1998 record apparent signals of major ice storms in 1920, 1979, and 1994. For the Walker Mountain site, our results suggest that during the period 1901-1998 the stand was affected by major ice storms in 1918 and 1994. This study suggests that den- drochronology provides a promising method for understanding fine-scale spatial patterns of ice storm disturbance in hardwood forests.