Vegetation development in a hardwood-forest chronosequence in Nova Scotia

1994 ◽  
Vol 24 (2) ◽  
pp. 260-271 ◽  
Author(s):  
M. Crowell ◽  
B. Freedman

Vegetation and aboveground biomass and nutrient capital (N, P, K, Ca, and Mg) were examined in a 22-stand, 75-year chronosequence within an angiosperm-dominated forest in Nova Scotia. Stands 20 years old and younger originated with clear-cutting, whereas older stands originated with wildfire. Early successional, ruderal species of vascular plants were prominent for ca. 5 years after clear-cutting, but they occurred as a part of a diverse, species-rich community dominated by more-tolerant species, many of which survived the disturbance of clear-cutting. The rate of accumulation of aboveground biomass averaged 2.2 t•ha−1•year−1 during the first 11 years after clear-cutting, 4.7 t•ha−1•year−1 between 11 and 30 years, and then decreased to 1.5 t•ha−1•year−1 between 30 and 75 years. Foliage biomass recovered to a quantity typical of mature stands within only 3–5 years of disturbance, as a result of the vigorous growth of both ground vegetation and stump sprouts of certain tree species. The patterns of accumulation of N, P, K, and Mg were similar to that of biomass, except that initially their relative rates of accumulation were faster because of the large proportion of nutrient-rich foliage in young stands. The accumulation of Ca was relatively slower, because of its large concentration in tree bark, a tissue whose proportion in the aboveground biomass reached a maximum much later than did foliage.

1986 ◽  
Vol 16 (2) ◽  
pp. 293-302 ◽  
Author(s):  
E. S. Wallace ◽  
B. Freedman

A postclear-cutting chronosequence of hardwood stands in Nova Scotia was examined for patterns of forest floor weight, concentration of selected nutrients, rate of potential insitu litter decomposition (litterbags), and potential lab ammonification and nitrification. Some evidence was found that the forest floor experiences weight loss following clear-cutting. However, the large weight losses and clear pattern of recovery described by others for New Hampshire hardwood chronosequences were not observed. The lack of close agreement may have been a result of intra- and inter-stand variation in forest floor weight in our study. This spatial variation was greater than any effect as a result of clear-cutting. There was no significant relationship between insitu weight loss of leaves or twigs with stand age. No clear-cutting effect was observed in the laboratory for potential ammonification, which occurred readily in all stands (three clear-cuttings, three mature stands). Limed materials produced significantly more mineralized N (nitrate N + ammonium N) than did unlimed materials. Concentrations of ammonium N in F and H horizon field material were significantly higher on clear-cuttings than in mature stands. However, since this measurement reflects net rather than total production, it is not evidence that higher rates of ammonification occurred on clear-cuttings. Potential nitrification was not an important process in F and H horizon materials at their natural pH. Nitrification occurred readily in limed materials, but there were no significant differences among different aged stands. Concentrations of nitrate N in field F and H horizon material were low for all stands, with a mean of 9 ± 7 ppm (n = 350). However, in 7% of field samples, nitrate N ≥ 15 ppm was found; in 2%, ≥30 ppm was found.


1953 ◽  
Vol 29 (3) ◽  
pp. 267-272 ◽  
Author(s):  
W. K. McGinn ◽  
A. G. Davidson

Studies were undertaken in Nova Scotia to determine (i) the effect of different cutting practices on the establishment of a RIBES population and of white pine regeneration, (ii) whether blister rust is a major factor in retarding the establishment of white pine regeneration, and (iii) the feasibility and cost of RIBES eradication as a direct control measure against blister rust. No relationship was found to exist between RIBES establishment and the degree of cutting. Uncut softwood stands, where white pine is the predominant species, show evidence of producing a future pine crop. Forest types supporting white pine appear to offer the best opportunities for pine reproduction where a clear-cutting operation has given the stand maximum opening. Results of the present study to date do not show that blister rust is a major factor in retarding the establishment of white pine regeneration. To eradicate RIBES from the study area by a complete systematic search required 1 man-hour per acre. Because of the small number of RIBES plants found and of the tendency for them to occur consistently in moist, low-lying habitats, a complete systematic search for these plants appears to be unnecessary. It is suggested that one man, trained to recognize RIBES and their probable location, could cover large forest tracts with a minimum of time expended in searching localities unlikely to support these plants.


2007 ◽  
Vol 121 (1) ◽  
pp. 76 ◽  
Author(s):  
David J. Garbary ◽  
Barry R. Taylor

Over 85 records of 23 species of blooming, herbaceous angiosperms were made at 19 sites in Antigonish County between 7 and 21 January 2006, when daytime temperatures reached 15°C. These observations followed an unusually warm fall and early winter. All species were observed on waste ground or in fields and garden plots, except for Epigaea repens L. which was part of ground vegetation in a sparsely wooded site. The primary families represented were Asteraceae (six species), Brassicaceae (six species) and Carophyllaceae (four species). The most commonly observed plants were Taraxacum officinale (L.) Weber (11 sites), Capsella bursa-pastoris (L.) Medik. (nine sites), Thlaspi arvense L. (three sites) and Stellaria media (L.) Vill. (four sites). Many plants and inflorescences were conspicuously frost-damaged, and flowers were rarely fully open. In several species, e.g., T. arvense and Cerastium vulgatum L., many individual plants looked normal and there was no evidence of frost damage. These observations are the latest flowering records for Nova Scotia.


1983 ◽  
Vol 29 (6) ◽  
pp. 644-648 ◽  
Author(s):  
Thu Kauri

A beech forest after clear-cutting was replanted with spruce. To study how this perturbation affected soil bacteria and their physiological capabilities, an investigation was undertaken 4 years after the change of forest type. Compared with an earlier study in the beech forest, from 1972 to 1975, conducted immediately before clear-cutting, bacterial numbers in the young spruce plantation had increased; an exception was the upper layer (A00), where the numbers decreased. The population densities of bacteria decomposing xylan, pectin, starch, cellulose, and chitin were estimated by a direct multipoint method. The numbers of bacteria in all the physiological groups studied were higher in 1979–1980, with the same exception as before (A00). The greatest changes occurred in the upper horizons. There were considerable changes in the soil environment after the former beech litter fall ceased; the forest floor became more exposed, and the ground vegetation changed. Changes took place in soil properties, such as organic matter and pH. A slight increase in pH was observed in all horizons except in A00, and organic matter increased in two of the horizons (A01/A1; A1).


Author(s):  
Л.Г. Ханина ◽  
L.G. Khanina

We have developed a system of plant functional groups for modeling dynamics of forest ground vegetation. Ecological and coenotic traits of species together with species life form and biomass values were used to classify species into the functional groups. Ground vegetation patches dominated by species of different plant functional groups were distinguished in the forest floor. We have characterized biomass of these patches by applying of statistical analysis of published data and results of our own field investigations combined into the database "Biomass". Biomass of vascular plants and bryophytes quite well differs between the patches. Variations of above and below ground biomass of vascular plants are minimal within the types of forest floor patches as compared to their variations within the plant functional groups and forest types. Database "Elements" on element concentrations of herbaceous species and cryptogams was also developed on the basis of results of field investigations in the North and the Middle Taiga. The functional groups of species well differ on the concentration of elements in plants forming a group. We have proposed a conceptual model of dynamics of ground forest vegetation; a model compatible with the individual-based EFIMOD model of forest growth and elements cycles in forest ecosystems. Spatial unit of the ground vegetation model is the same as spatial unit of the EFIMOD (0.5×0.5 м); it is a patch of the forest floor dominated by species from one or more functional groups.


Silva Fennica ◽  
2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Jaana Luoranen ◽  
Heli Viiri

Over 20% of regeneration operations will be on drained peatland in the next decade in Finland. There are only a few studies comparing the planting success and the risk of pine weevil ( (L.) feeding damage on mineral soil and drained peatland. Thirty sites planted with Norway spruce ( (L.) H. Karst.) container seedlings in 2009 in Southern and Central Finland were inventoried three growing seasons after planting. Prediction models for the probability of survival, pine weevil damage and the presence of ground vegetation cover were done separately for peatland and mineral soil sites. The planting success was 17% lower on peatland sites (1379 surviving seedlings ha) than on mineral soil (1654 seedlings ha). The factors explaining the survival were the ground vegetation cover and type of the planting spot on the peatland, and the ground vegetation cover on mineral soil. On mineral soil, 76% of the planting spots were on cultivated mineral soil while on peatland only 28% of the seedlings were planted on similar spots. There were also fewer seedlings that were surrounded by dense ground vegetation on mineral soil (4%) than on peatland (14%). Pine weevil feeding damage did not differ significantly on peatland (23%) or mineral soil (18%). The more time there was from clear-cutting, the more the probability of pine weevil feeding damage was reduced on both soil classes. Additionally, cover vegetation in the vicinity of the seedlings increased on mineral soil. Cultivated planting spots, especially those covered by mineral soil, prevented pine weevil feeding and reduced the harmful effects of vegetation on the seedlings both on mineral soil and peatland.Hylobius abetisPicea abies–1–1


2005 ◽  
Vol 9 (6) ◽  
pp. 657-674 ◽  
Author(s):  
A. Laurén ◽  
L. Finér ◽  
H. Koivusalo ◽  
T. Kokkonen ◽  
T. Karvonen ◽  
...  

Abstract. A two dimensional model, FEMMA, to describe water and nitrogen (N) fluxes within and from a forested first-order catchment (Kangasvaara in Eastern Finland) was constructed by linking the most significant processes affecting the fluxes of water, ammonium, nitrate and dissolved organic nitrogen along a hillslope from the water divide to the stream. The hillslope represents the average flowpath of water in the catchment and the model was used to estimate the N fluxes for a catchment in eastern Finland before and after clear-cutting. The simulated results were in reasonable agreement with the nitrate, dissolved organic N and dissolved total N measurements from the study catchment and with other results in the literature. According to the simulations, the major sinks of N after clear-cutting were immobilisation by soil microbes, uptake by ground vegetation and sorption to soil. These sinks increased downslope from the clear-cut area, indicating the importance of an uncut buffer zone between the stream and the clear-cut area in reducing N exports. The buffer zone retained 76% of the N flux coming from the clear-cut area. Nitrification was a key process in controlling the N export after clear-cutting and N increases were mainly as nitrate. Most of the annual N export took place during the spring flood, when uptake of N by plants was minimal.


1985 ◽  
Vol 15 (2) ◽  
pp. 400-409 ◽  
Author(s):  
Henry L. Gholz ◽  
Glenn M. Hawk ◽  
Alsie Campbell ◽  
Kermit Cromack Jr. ◽  
Alfred T. Brown

Aboveground biomass and leaf area, net primary production, and nutrient cycling through vegetation were studied for 3 years after clear-cutting (stems only) of a 10.24-ha watershed in the Oregon Cascade Mountains. The riparian zone and four main habitats were analyzed separately. In 3 years, aboveground net primary production increased from 5 to 112 g•m−2•year−1 in the ridgetop habitat; midsummer aboveground biomass increased from 8 to 196 g/m2 in the riparian zone and from 198 to 327 g/m2 on the ridgetop. Other values were intermediate to these. Litter fall of species with perennial aboveground parts averaged 20–27% of standing biomass. Native annuals, especially Araliacalifornica Wats., dominated the riparian zone. Seneciosylvaticus L., an introduced species, dominated most of the rest of the watershed, except for the ridgetop habitat, which was dominated by residual woody shrubs. Uptake of N exceeded losses in streamflow the 1st year and was six times greater in the 2nd; uptake of P and K in that year was 2.5 and 3 times greater than losses. In the 3rd year, total uptake of K (2.5 g•m−2•year−1) equaled the preclear-cutting level, and uptake of N (1.3 g•m−2•year−1) and P (0.3 g•m−2•year−1) was about half that level. No correlation was found between plant uptake and nutrient loss in streamflow. Uptake of all elements exceeded return through leaching and litter fall by 16%, except that of Mg, which exceeded return by 44%. Because of early dominance by species with annuals, the proportion of elements redistributed internally by vegetation was generally low. The amount of nutrients in flux through vegetation, atmosphere, and stream was small in comparison to the amount lost in the removal of tree stems.


1993 ◽  
Vol 23 (6) ◽  
pp. 1233-1239 ◽  
Author(s):  
David Paré ◽  
Keith Van Cleve

Nutrient content and biomass of aboveground annual production, and nutrient content of total aboveground biomass, of 14-year-old assemblages of plants developing on harvested white spruce (Piceaglauca (Moench) Voss) sites were estimated by vegetation harvesting and compared with values previously measured in mature white spruce stands. The aboveground biomass production of 14-year-old regenerating trembling aspen (Populustremuloides Michx.) clumps was 3 times higher than the aboveground production of mature white spruce stands, while the aboveground production of other regenerating communities was lower or equivalent to the production of mature white spruce. However, the nutrient content of aboveground current biomass was greater in all regenerating communities than in mature white spruce stands, except on regenerating sites where the forest floor was absent. The amount of nutrient incorporated in current aboveground biomass was 5 times greater in trembling aspen clumps than in mature white spruce stands. Furthermore, the total N, P, and K content of aboveground vegetation corresponded, in 14-year-old trembling aspen clumps, to a value that ranged from 50 to 109% of the amount found in the aboveground biomass of mature white spruce forests, while this value ranged from 4 to 14% on other regeneration types. Trembling aspen and balsam poplar (Populusbalsamifera L.) both showed the greatest concentrations of N and P in foliar litter fall. These observations suggest that the development of a trembling aspen clump after clear-cutting contributes to the acceleration of nutrient cycling. On the other hand, the development of herbaceous communities during the same period after clear-cutting was accompanied by much lower nutrient cycling rates in the aboveground portion of the vegetation.


Sign in / Sign up

Export Citation Format

Share Document