Patterns of canopy interception and throughfall along a topographic sequence for black spruce dominated forest ecosystems in northwestern Ontario

2003 ◽  
Vol 33 (6) ◽  
pp. 1046-1060 ◽  
Author(s):  
Dave M Morris ◽  
Alan G Gordon ◽  
Andrew M Gordon
Keyword(s):  
Black Spruce ◽  
Inorganic Nitrogen ◽  
The Other ◽  
Organic N ◽  
Nutrient Concentrations ◽  
Canopy Interception ◽  
Area Index ◽  
Northwestern Ontario ◽  
Other Hand ◽  
Study Sites

A 3-year (1993–1995) study was conducted to describe both the spatial (within- and between-site) and temporal (monthly) patterns associated with canopy interception, throughfall, and net forest water along a black spruce (Picea mariana (Mill.) BSP) topo-sequence situated in northwestern Ontario. This site array included (1) an upland, well-drained, mineral soil site; (2) a poorly drained, midslope, wet mineral site; and (3) a treed wetland on organic (peat) soil. Bulk precipitation (BP) and throughfall (TF) were collected, on an event basis (63 events, over 4800 samples analyzed), using standard collecting devices and analyzed for total Kjeldahl nitrogen (TKN), ammonium (NH4+), nitrate (NO3–), total phosphorus (TP), potassium (K), calcium (Ca), and magnesium (Mg). Comparison of BP and TF data suggested that an enrichment of K (190%), Mg (115%), and Ca (70%) occurred during canopy interactions. On the other hand, inorganic nitrogen (NH4+: –73%; NO3–: –47%), and to a lesser extent TP (–35%), rates declined. TKN, however, remained the same, suggesting that inorganic N reductions were offset by organic N inputs. Downward shifts in pH were also detected for TF (4.45–4.48), as compared with the pH of BP (4.52–4.80). Although all study sites received similar rainfall amounts, the more productive sites (i.e., carrying greater foliar mass, higher leaf area index) had lower TF volumes (i.e., higher interception rates) but higher macronutrient returns to the forest floor. This increase in macronutrient deposition was directly related to substantial increases in nutrient concentrations, which, in turn, suggested a greater degree of canopy interaction and (or) leaching on these sites. Throughfall pH, however, was not significantly different across the three study sites. With respect to temporal patterns, the major cations (K+, Ca2+, Mg2+) demonstrated an increasing trend in concentration levels in TF as the season progressed to a maximum in October. TKN and TP concentrations, on the other hand, maintained relatively stable levels throughout the summer, peaking in September, but dropping substantially in October as metabolic processes slowed and the supply of these nutrients to the foliage was reduced. Even with the increase in base cation concentration, throughfall pH shifted downward to 4.3 or below by late fall.

Effets de la coupe à blanc et de la coupe par bandes sur la régénération obtenue après 5 ans dans des pessières noires du Québec

1995 ◽  
Vol 25 (2) ◽  
pp. 329-342 ◽  
Author(s):  
Pierre Pominville ◽  
Jean-Claude Ruel
Keyword(s):  
Black Spruce ◽  
Spruce Budworm ◽  
Lower Proportion ◽  
The Other ◽  
Balsam Fir ◽  
Clear Cutting ◽  
Other Hand ◽  
The One ◽  
Almost All ◽  
Coupe À Blanc

An experiment was conducted to compare the effects of traditional clear-cutting with those of strip cutting on regeneration of black spruce, Piceamariana (Mill.) B.S.P., stands on scarified and unscarified uplands and on lowlands. To that effect, regeneration surveys were done before cutting, in the following year, and 3 and 5 years after cutting. Five years after harvesting, strip cutting led to higher coniferous stocking than clear-cutting on scarified uplands and on lowlands. On unscarified uplands, the gain attributable to strip cutting was not significant. The coniferous stocking of strip cuts on scarified uplands was not greater than on unscarified uplands. So the efficiency of scarification could not be proved in that study. Stocking obtained after 5 years remained closely related to the one observed immediately after harvesting in the strip cufs as in the clear-cuttings. This is particularly true for balsam fir, Abiesbalsamea (L.) Mill. In the strip cuts, the balsam fir stocking was constant while the one of black spruce increased. This could have an impact on the evolution of the composition of the new stands and, consequently, on their vulnerability to spruce budworm, Choristoneurafumiferana (Clem.). The majority of the clear-cuttings were well regenerated 5 years after harvesting. Their average coniferous stocking was slightly above 60%. However, 48% of the clear-cuttings did not reach this level when only unscarified plots on uplands were considered. Advance growth was abundant in those plots but suffered high losses during harvesting. Consequently, reducing the losses during harvesting would result in a lower proportion of clear-cuttings with insufficient coniferous stocking 5 years after cutting. On the other hand, almost all the strip cuts with insufficient regeneration after harvesting were well regenerated 5 years later. Thus, strip cutting could be an interesting option on sites with insufficient advance growth and on sites well regenerated before cutting but where important losses during harvesting are anticipated.

Habitat-dependent morphological and chemical variation in Picea mariana from northwestern Ontario

1983 ◽  
Vol 61 (6) ◽  
pp. 1573-1579 ◽  
Author(s):  
William H. Parker ◽  
P. Knowles ◽  
F. Bennett ◽  
A. Gray ◽  
T. Krickl
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Alluvial Soil ◽  
Electrophoretic Analysis ◽  
The Other ◽  
Northwestern Ontario ◽  
Local Site ◽  
Thunder Bay ◽  
Heavy Soil ◽  
Sphagnum Bog

To determine whether local site differences corresponded to any morphological or chemical differentiation in Picea mariana, 10 cone-bearing trees were sampled from each of three semiadjacent stands near the Matawin River, Thunder Bay District, Ont.: (i) an upland forest on well-drained alluvial soil, (ii) an abandoned pasture on heavy soil, and (iii) a wet sphagnum bog. Nine cone characters and eight needle and twig characters were scored and analyzed. Differences among sites were generally small. Principal-components analysis demonstrated two major, independent trends of variation, one attributable mainly to cone characters and the other to needle characters. Bog trees tended to be more variable than the others with respect to cone characters but had similar levels of variation for needle and twig characters. Further comparisons were made based on foliar flavonoids of the 30 trees and isozyme characteristics of an expanded sampling of 60 trees. Flavonoid analysis indicated that a fraction of the bog trees possessed flavonoid diglycosides not present in the other trees. Five polymorphic enzyme systems were detected in electrophoretic analysis. Trees from the three sites had similar isozyme patterns with the exception of three bands that were unique to the bog site trees. Thus, the bog trees were more variable for cone, flavonoid, and isozyme characters but exhibited no greater variability for needle and twig characters. However, none of the data gave an indication of discrete ecotypes of black spruce corresponding to upland and lowland sites.

scholarly journals Rainfall Partitioning in Chinese Pine (Pinus tabuliformis Carr.) Stands at Three Different Ages

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 243
Author(s):  
Lingling Dong ◽  
Hairong Han ◽  
Fengfeng Kang ◽  
Xiaoqin Cheng ◽  
Jinlong Zhao ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Northern China ◽  
Rainfall Amount ◽  
Pine Forest ◽  
The Other ◽  
Stand Age ◽  
Canopy Interception ◽  
Chinese Pine ◽  
Other Hand ◽  
Chinese Pine Forest

Chinese pine (Pinus tabuliformis Carr.) is the main forest species in northern China, with the potential to dramatically affect biotic and abiotic aspects of ecosystems in this region. To discover the rainfall partitioning patterns of different growth periods of Chinese pine forest, we studied the throughfall (Tf), stemflow (Sf) and canopy interception (I) in three stand ages (40-, 50-, 60-year-old) in Liaoheyuan Natural Reserve of Hebei Province during the growing seasons of 2013 and 2014, and analyzed effect of rainfall amount, rainfall intensity, and canopy structure on rainfall partitioning in Chinese pine forest. The results showed that throughfall decreased with the stand age, accounting for 78.8%, 74.1% and 66.7% of gross rainfall in 40-, 50- and 60-year-old Chinese pine forests, respectively. Canopy interception, on the other hand, increased with the stand age (20.4%, 24.8%, and 32.8%, respectively), while the pattern in stemflow was less clear (0.8%, 1.1%, and 0.6%, respectively). As rainfall intensity increased, the Tf and Sf increased and I declined. Additionally, our results showed that leaf area index (LAI) and the diameter at breast height (DBH) increased with age in Chinese pine stands, probably explaining the similar increase in canopy interception (I). On the other hand, the mean leaf angle, openness, gap fraction all decreased with the stand age. Stepwise regression analysis showed that the rainfall amount and LAI were the major determinants influencing the rainfall partition. Our study highlights the importance of stand age in shaping different forest canopy structures, and shows how age-related factors influence canopy rainfall partitioning. This study also significantly adds to our understanding the mechanisms of the hydrological cycle in coniferous forest ecosystems in northern China.

scholarly journals Nutritional disorder in Pfaffia glomerata by mercury excess in nutrient solution

2015 ◽  
Vol 46 (2) ◽  
pp. 279-285 ◽  
Author(s):  
Nicéia Spanholi Calgaroto ◽  
Fernando Teixeira Nicoloso ◽  
Luciane Belmonte Pereira ◽  
Denise Cargnelutti ◽  
Fabiane Goldschmidt Antes ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
The Other ◽  
Nutrient Concentrations ◽  
Nutritional Disorder ◽  
Pfaffia Glomerata ◽  
P Concentration ◽  
Other Hand ◽  
Fe And Mn ◽  
Tissue Nutrient Concentrations ◽  
Mn Concentrations

ABSTRACT: The mineral nutritional homeostasis in response to different concentrations of Hg (0, 25 and 50μM) was evaluated in Pfaffia glomerata plant. The exposure to the highest level of Hg (50µM) caused a decreasing in shoot and root fresh weights of 15.5% and 20%, respectively. Both shoot and root Hg concentrations increased linearly with increasing external Hg concentrations. Ca concentration decreased in shoot only at 50µM Hg, whereas shoot K and Mg concentrations decreased at both 25 and 50µM Hg, when compared to the control. A significant decrease in Cu, Zn, Fe and Mn concentrations in plants exposed to Hg was observed, but most Zn, Mn, and Cu in the roots. On the other hand, P concentration increased in both root and shoot of plants exposed at 25 and 50µM Hg, whereas Na concentration increased only in the root at 25 and 50µM Hg exposure. In general, tissue nutrient concentrations in P. glomerata plantlets exposed to Hg were significantly decreased, which indicates that the Hg may cause alteration on the mineral nutritional homeostasis of this species.

scholarly journals Studying the impacts of harvest intensity on site productivity of Ontario's black spruce ecosystems

1999 ◽  
Vol 75 (3) ◽  
pp. 439-445 ◽  
Author(s):  
Dave M. Morris ◽  
Dan R. Duckert
Keyword(s):  
Black Spruce ◽  
Complete Removal ◽  
Site Productivity ◽  
Northwestern Ontario ◽  
Biomass Removal ◽  
Core Study ◽  
Group A ◽  
Tree Length ◽  
Study Sites

As a result of a Class Environmental Assessment, the Ontario Ministry of Natural Resources (OMNR) was mandated to design and implement a research project pertaining to the effects of full-tree harvesting on long-term site productivity. This project, initiated in 1991, was designed to focus on ecosystem processes and the changes occurring to these processes after harvesting (e.g., quantifying the disruption and recovery) for the black spruce working group. A series of replicated, experimental harvest treatments with varying degrees of biomass removal were conducted on nine core study sites, representing different black spruce ecosites located in northwestern Ontario, Canada. The harvest treatments included: uncut — controls, tree length — delimbed at the stump, full tree — delimbed at the roadside, full-tree chipping — chipped debris was returned to the harvest plot, and whole tree — complete removal of vegetation and forest floor. Each site consisted of 16 plots, three replicates of the four harvest treatments (30 m × 30 m plots) and four replicates of the control plots (50 m × 50 m plots). Work on this project is anticipated to continue for a minimum of fifteen years to detail the early and most dynamic stages of post-harvest recovery. Key words: black spruce, site productivity, nutrient cycling, harvesting impacts

scholarly journals Notes on the Herpetofauna of Kampung Giam, Padawan, Sarawak

1970 ◽  
Vol 3 (2) ◽  
pp. 47-52
Author(s):  
Ramlah Zainudin ◽  
Jennifer Ubung Nawan ◽  
Marcie Elene Marcus Jopony ◽  
Muhammad Fadzil Amram ◽  
Nordianah Nasip ◽  
...  
Keyword(s):  
Conservation Management ◽  
The Other ◽  
Species Assemblage ◽  
Sticky Traps ◽  
Other Hand ◽  
The Family ◽  
Study Sites

Padawan lies at one of the proposed Sarawak Geopark, yet information on the herpetofauna of the area islimited. A survey was conducted from 16 August 2008 to 24 August 2008 to determine species assemblage andrelative abundance of herpetofauna at Kampung Giam, Padawan. Sampling involved stream and forest transects,quadrat, pitfall and sticky traps at four study sites along Sungai Sewa. A total of 13 species of frogs (62individuals), eight species of lizards (nine individuals) and four species of snake (one individual each) werecaptured. The area was dominated by the family of Ranidae (83.9%), followed by Bufonidae (8%),Dicroglossidae (3.2%), Microhylidae (3.2%) and Megophryidae (1.6%). The most abundant and dominantspecies was Odorrana hosii, with 36 individuals caught. In addition three endemic Bornean frogs namelyLimnonectes leporinus, Meristogenys phaeomerus and Meristogenys orphnocnemis were also captured in thisstudy, which account for 33.33% endemism. The reptiles caught, on the other hand, were relatively low withonly 12 species and 13 individuals captured. Nevertheless this study provides an increment of Sarawak faunaldatabase for conservation management of Bornean fauna as well as the Sarawak Geopark.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

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