Seasonal and diurnal trends of heat pulse velocity in Douglas-fir and ponderosa pine

1986 ◽  
Vol 16 (4) ◽  
pp. 814-821 ◽  
Author(s):  
W. Lopushinsky

Seasonal trends of heat pulse velocity in the trunks of 55-year-old ponderosa pine (Pinusponderosa Dougl. ex Laws.) and Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) trees showed large yearly variations related to weather patterns. Onset of sap movement in the spring, seasonal variations, and summer declines in response to decreasing moisture were similar for Douglas-fir and ponderosa pine. When soil moisture was not limiting, rates of heat pulse velocity in both species were significantly related to air temperature, solar radiation, and vapor pressure deficit. As soil moisture decreased during the summer, rates of heat pulse velocity no longer followed evaporative demand. In both species, sap movement also occurred at night. Diurnal trends of heat pulse velocity also were similar in both species. During early summer, maximum heat pulse velocity occurred at midday; in the fall, maximum rates occurred earlier. The similarity of seasonal and diurnal trends of heat pulse velocity and responses to variation in site conditions suggest that on the site studied, transpiration behavior in ponderosa pine and Douglas-fir trees generally is similar.

2006 ◽  
Vol 82 (5) ◽  
pp. 723-732 ◽  
Author(s):  
Alan Vyse ◽  
Christine Ferguson ◽  
Suzanne W Simard ◽  
Tamaki Kano ◽  
Pasi Puttonen

The effects of partial cutting on seedling growth of three conifer species were studied at a very dry, hot interior Douglas-fir site near Kamloops, British Columbia. Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and ponderosa pine (Pinus ponderosa Dougl. ex. P. & C. Laws.) seedlings were planted in mechanically prepared 50 cm × 50 cm patches under different canopy conditions created by harvesting 60% of the original stand volume. The prepared areas were selected to represent canopy closures from open to closed, slopes from 0 to 60%, and all aspects. After six years, survival of Douglas-fir, lodgepole pine and ponderosa pine was 78%, 76% and 70%, respectively. Light level had a strong influence on survival and condition. Growth of all species increased linearly with light, and was greatest for lodgepole pine, followed by ponderosa pine and Douglas-fir. Multiple regression analysis showed that six-year seedling size was most significantly affected by total light, and only occasionally by aspect, slope, or crown closure. The best models explained 53%, 47% and 42% of the variation in diameter of lodgepole pine, ponderosa pine, and Douglas-fir, respectively. Natural abundance 13C was positively correlated with light and soil moisture availability, reflecting higher photosynthetic capacity of all species in the wetter, open canopy conditions. Patterns in isotopic discrimination also indicated greater water use efficiency of Douglas-fir and ponderosa pine than lodgepole pine under low light conditions. Underplanting stands thinned to a basal area of less than 15m2 per ha offers a solution to regeneration difficulties on hot, dry Interior Douglas-fir sites. Key words: partial cutting, Douglas-fir, lodgepole pine, ponderosa pine, light, soil moisture, 13C, growth, survival, Opax Mountain Silvicultural Systems Project


2002 ◽  
Vol 32 (10) ◽  
pp. 1858-1874 ◽  
Author(s):  
Emma Watson ◽  
Brian H Luckman

A network of 53 ring-width chronologies has been developed from low-elevation stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco, n = 40) and ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws., n = 13) in the southern Canadian Cordillera. Relationships between the chronologies and monthly, seasonal, and annualized climatic parameters (precipitation, temperature, and Palmer Drought Severity Index (PDSI)) were investigated using correlation analyses. The results indicate that tree growth at the sites is most strongly related to water availability during the growing season months. Although the response of the two species is similar, Douglas-fir show a slightly stronger correlation with seasonalized precipitation for the prior year and early summer whereas ponderosa pine correlate most strongly with current year and late (July) summer precipitation. Maximum correlations for both species occur with annual precipitation totals. The precipitation signal is slightly weaker in the more northerly Douglas-fir chronologies in British Columbia and the higher elevation sites in southwestern Alberta. Correlations with available PDSI records are generally comparable with those from precipitation variables, but the limited number of PDSI records and the availability of more proximal and better correlated precipitation records indicated that annual (summer–summer) precipitation totals provide the best possibilities to develop regional, moisture-related proxy climate records from these data. Analysis of earlywood and latewood chronologies for 28 sites (mainly Douglas-fir) indicates that earlywood width is most consistently and strongly correlated with precipitation in the previous summer (July and August), and latewood width is more strongly related to precipitation in the current summer (June and July). The results of these analyses demonstrate considerable potential for reconstructing annual (and (or) summer) precipitation for sites across the region.


2009 ◽  
Vol 22 (18) ◽  
pp. 4747-4758 ◽  
Author(s):  
Matteo Zampieri ◽  
Fabio D’Andrea ◽  
Robert Vautard ◽  
Philippe Ciais ◽  
Nathalie de Noblet-Ducoudré ◽  
...  

Abstract Drought in spring and early summer has been shown to precede anomalous hot summer temperature. In particular, drought in the Mediterranean region has been recently shown to precede and to contribute to the development of extreme heat in continental Europe. In this paper, this mechanism is investigated by performing integrations of a regional mesoscale model at the scale of the European continent in order to reproduce hot summer inception, starting with different initial values of soil moisture south of 46°N. The mesoscale model is driven by the large-scale atmospheric conditions corresponding to the 10 hottest summers on record from the European Climate Assessment dataset. A northward progression of heat and drought from late spring to summer is observed from the Mediterranean regions, which leads to a further increase of temperature during summer in temperate continental Europe. Dry air formed over dry soils in the Mediterranean region induces less convection and diminished cloudiness, which gets transported northward by occasional southerly wind, increasing northward temperature and vegetation evaporative demand. Later in the season, drier soils have been established in western and central Europe where they further amplify the warming through two main feedback mechanisms: 1) higher sensible heat emissions and 2) favored upper-air anticyclonic circulation. Drier soils in southern Europe accelerate the northward propagation of heat and drying, increasing the probability of strong heat wave episodes in the middle or the end of the summer.


2019 ◽  
Vol 16 (1) ◽  
pp. 25-35 ◽  
Author(s):  
N.A. Komaromi ◽  
A.V. Putchkov ◽  
V.Yu. Nazarenko

A total of 54 species in 35 genera of Curculionidae are registered in the urbocenoses of Kharkiv city. Only three species, Exomias pellucidus, Otiorhynchus raucus and Ot. ovatus, are recorded as dominants. Some other species (Urometopus nemorum, Sciaphobus squalidus and Glocianus punctiger) are sporadically noted in some sites as subdominants. The total number of species turned out to be higher in the herpetobios of plantings at periphery (31), slightly lower in private farmlands of the city (21), parks and plantings of the center (17 each), but minimal in suburban forests (11 species). The highest quantity of specimens were observed for the plantations of the center and margins of city: nevertheless, minimal quantity of specimens was registered at parks and woods. The maximum number of species (including all cenoses) was recorded from the end of April to first decade of May (28 species). From May to the end of June 15–18 species were registered. Ten species were recorded at July, and only six species at August. A slight rise was noted from the end of August to mid-September (11 species). In biotopes where Exomias pellucidus appeared to be the monodominant, the seasonal dynamic density of weevils reached a peak at late May or early June, but the significant decline was observed from early June to July. At the sites with several dominants, two or three peaks were registered: at spring (May) and at mid-summer (end of June or beginning of July). Furthermore, the number of weevils decreased gradually, but some species of Curculionidae were rather abundant even from the end of summer to September–October. The spring increase is reasoned by high density of species in the genus Otiorhynchus; the peak in early summer (maximum) is caused by the increased activity of majority of dominant species; the autumn peak is also caused by the high number of species of the genus Otiorhynchus. The level of sex index (by the example of E. pellucidus) differed significantly at all plots. It was higher for the plantations at the periphery of the city (0.70), and it was minimal at private farmlands (0.20). Relative conjugacy of sex index and dynamic density were not observed: the maximum abundances of quantity of Curculionidae were recorded 20–30 days earlier than the maximal numbers of the sex index.


Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.


2004 ◽  
Vol 57 (6) ◽  
pp. 661 ◽  
Author(s):  
Yuguang Bai ◽  
Don Thompson ◽  
Klaas Broersma

Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 98-101 ◽  
Author(s):  
John C. Tappeiner ◽  
Steven R. Radosevich

An experiment was established in 1961 to determine the influence of bearmat (Chamaebatia foliolosa Benth.) competition on ponderosa pine (Pinus ponderosa Laws.) survival and growth. Ponderosa pine seedlings were planted in bearmat which was: (A) untreated, (B) sprayed with a mixture of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], and (C) eliminated by a combination of herbicide, clipping sprouts, and trenching to prevent root and rhizome invasion. Ponderosa pine survival after 19 yr averaged 9%, 66%, and 90%, respectively, for the three treatments. Tree height after 19 yr averaged 1.6, 1.9, and 5.7 m for treatments A, B, and C, respectively. Soil moisture use was initially less on the herbicide-treated than on the untreated plots, but bearmat quickly sprouted after application to compete with the pine seedlings for moisture. After 19 yr the bearmat was more dense and appeared to be more vigorous on the sprayed plots than on those receiving no treatment. We estimate that 75% reduction in net wood production could result after 50 yr on this site from bearmat competition.


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