Long-Term Thinning Effects on the Leaf Area of Pinus strobus L. as Estimated from Litterfall and Individual-Tree Allometric Models

The invasive pine wood nematode (PWN), Bursaphelenchus xylophilus, causal agent of pine wilt disease, was first reported in Europe, near Lisbon, in 1999, and has since then spread to most of Portugal. We here modelled the spatiotemporal patterns of future PNW natural spread in the Iberian Peninsula, as dispersed by the vector beetle Monochamus galloprovincialis, using a process-based and previously validated network model. We improved the accuracy, informative content, forecasted period and spatial drivers considered in previous modelling efforts for the PWN in Southern Europe. We considered the distribution and different susceptibility to the PWN of individual pine tree species and the effect of climate change projections on environmental suitability for PWN spread, as we modelled the PWN expansion dynamics over the long term (>100 years). We found that, in the absence of effective containment measures, the PWN will spread naturally to the entire Iberian Peninsula, including the Pyrenees, where it would find a gateway for spread into France. The PWN spread will be relatively gradual, with an average rate of 0.83% of the total current Iberian pine forest area infected yearly. Climate was not found to be an important limiting factor for long-term PWN spread, because (i) there is ample availability of alternative pathways for PWN dispersal through areas that are already suitable for the PWN in the current climatic conditions; and (ii) future temperatures will make most of the Iberian Peninsula suitable for the PWN before the end of this century. Unlike climate, the susceptibility of different pine tree species to the PWN was a strong determinant of PWN expansion through Spain. This finding highlights the importance of accounting for individual tree species data and of additional research on species-specific susceptibility for more accurate modelling of PWN spread and guidance of related containment efforts.

Download Full-text

Corn and Velvetleaf (Abutilon theophrasti) Growth and Transpiration Efficiency under Varying Water Supply

Weed Science ◽

10.1614/ws-d-15-00124.1 ◽

2016 ◽

Vol 64 (4) ◽

pp. 596-604

Author(s):

Logan G. Vaughn ◽

Mark L. Bernards ◽

Timothy J. Arkebauer ◽

John L. Lindquist

Keyword(s):

Water Supply ◽

Soil Water ◽

Leaf Area ◽

Biomass Accumulation ◽

Transpiration Efficiency ◽

Plastic Bags ◽

Comparative Response ◽

Competitive Success ◽

Daily Transpiration

The supply of soil resources is critical for the establishment and long-term competitive success of a plant species. Although there is considerable research on the effects of water supply on crop growth and productivity, there is little published research on the comparative response of crops and weeds to limiting soil water supply. The objective of this research was to determine the growth and transpiration efficiency of corn and velvetleaf at three levels of water supply. One corn or velvetleaf plant was grown in a large pot lined with plastic bags. When seedlings reached 10 cm, bags were sealed around the base of the plant, so the only water loss was from transpiration. Daily transpiration was measured by weighing the pots at the same time each day. The experiment was conducted in the fall of 2007 and in the spring of 2008. Four replicates of each species–water treatment were harvested periodically to determine biomass accumulation and leaf area. The relationship between cumulative aboveground biomass and water transpired was described using a linear function in which the slope defined the transpiration efficiency (TE). Corn TE was greater than velvetleaf TE in all treatments during both trials. In the fall trial, corn TE was 6.3 g kg–1, 47% greater than that of velvetleaf TE. In the spring trial, TEs of both species were lower overall, and corn TE increased with declining water supply. Corn produced more biomass and leaf area than velvetleaf did at all water-supply levels. Velvetleaf partitioned more biomass to roots compared with shoots during early growth than corn did. The ability of corn to generate more leaf area and its investment in a greater proportion of biomass into root growth at all levels of water supply may enable it to more-effectively avoid velvetleaf interference under all levels of soil-water supply.

Download Full-text

Evaluating the influence of stem form and damage on individual-tree diameter increment and survival in the Acadian Region: implications for predicting future value of northern commercial hardwood stands

Canadian Journal of Forest Research ◽

10.1139/cjfr-2018-0081 ◽

2018 ◽

Vol 48 (9) ◽

pp. 1007-1019 ◽

Cited By ~ 1

Author(s):

Mark Castle ◽

Aaron Weiskittel ◽

Robert Wagner ◽

Mark Ducey ◽

Jereme Frank ◽

...

Keyword(s):

Growth And Yield ◽

Tree Level ◽

Permanent Plots ◽

Stem Form ◽

Individual Tree ◽

Tree Diameter ◽

Diameter Increment ◽

Hardwood Species ◽

Future Value

Northern hardwood species display a variety of forms and defects that can reduce stem quality and complicate their timber management. However, for the most part, growth and yield models do not account for the influence of stem form and damage. This study determined the influence of stem form and damage on growth, survival, and projected future sawlog value among several northern commercial hardwood species. To accomplish this, hardwood trees on 112 permanent plots across three long-term research sites in Maine were assigned stem form and risk classes using a tree classification system developed in New Brunswick. A highly significant influence of stem form and risk on annualized individual-tree diameter increment and survival was found. Inclusion of these equations into a regional growth and yield model highlighted the importance of stem form and defects on long-term simulations as projected stand-level future value was significantly reduced by over 17%, on average (range of 13% to 28%), when compared with projections that did not include that tree-level information. The results highlight the importance of stem form and defects, as well as the need to account for them, in growth and yield applications that assess the forecasted value of commercially important hardwood stands.

Download Full-text

Long-term development of transition hardwood and Pinus strobus - Quercus mixedwood forests with implications for future adaptation and mitigation potential

Forest Ecology and Management ◽

10.1016/j.foreco.2021.119654 ◽

2021 ◽

Vol 501 ◽

pp. 119654

Author(s):

Peter W. Clark ◽

Anthony W. D'Amato

Keyword(s):

Pinus Strobus ◽

Mitigation Potential ◽

Mixedwood Forests ◽

Adaptation And Mitigation

Download Full-text

Effects of overstory competition on canopy recruitment patterns of naturally regenerated longleaf pine on two site types

Canadian Journal of Forest Research ◽

10.1139/cjfr-2019-0343 ◽

2020 ◽

Vol 50 (7) ◽

pp. 624-635

Author(s):

Patrick J. Curtin ◽

Benjamin O. Knapp ◽

Steven B. Jack ◽

Lance A. Vickers ◽

David R. Larsen ◽

...

Keyword(s):

Longleaf Pine ◽

Pinus Palustris ◽

Height Growth ◽

Growth Patterns ◽

High Density ◽

Low Density ◽

Individual Tree ◽

Pine Trees ◽

Overstory Trees

Recent interest in continuous cover forest management of longleaf pine (Pinus palustris Mill.) ecosystems raises questions of long-term sustainability because of uncertainty in rates of canopy recruitment of longleaf pine trees. We destructively sampled 130 naturally regenerated, midstory longleaf pines across an 11 300 ha, second-growth longleaf pine landscape in southwestern Georgia, United States, to reconstruct individual tree height growth patterns. We tested effects of stand density (using a competition index) and site quality (based on two site classifications: mesic and xeric) on height growth and demographics of midstory trees. We also compared height growth of paired midstory and overstory trees to infer stand regeneration and recruitment dynamics. In low-density stands, midstory trees were younger and grew at greater rates than trees within high-density stands. Midstory trees in low-density stands were mostly from a younger regeneration cohort than their paired overstory trees, whereas midstory–overstory pairs in high-density stands were mostly of the same cohort. Our results highlight the importance of releasing midstory longleaf pine trees from local competition for sustained height growth in partial-harvesting management systems. They also demonstrate patterns of long-term persistence in high-density stands, indicating flexibility in the canopy recruitment process of this shade-intolerant tree species.

Download Full-text

Ontario, Canada’s LTSP Experience: Forging Lasting Research Partnerships and the Adaptive Management Cycle in Action

Journal of Forestry ◽

10.1093/jofore/fvaa002 ◽

2020 ◽

Vol 118 (3) ◽

pp. 337-351

Author(s):

Dave M Morris ◽

Rob L Fleming ◽

Paul W Hazlett

Keyword(s):

Adaptive Management ◽

Management Practices ◽

Forest Policy ◽

Lessons Learned ◽

Soil Productivity ◽

Research Partnerships ◽

Foliar Nutrition ◽

Individual Tree ◽

The North

Abstract In this paper, we summarize Ontario’s Long-term Soil Productivity (LTSP) experience focusing on our efforts to forge lasting research partnerships, highlight the approaches we feel were effective in getting emerging science into forest policy within an adaptive management (AM) framework, and describe the future direction of Ontario’s LTSP program as new policy issues are emerging as part of the continuous AM cycle. Fourteen installations were established on nutrient-poor, conifer-dominated sites, considered to be the most sensitive to increased biomass removals. From 1993 to 1995, all sites were clearcut-harvested, with replicated (three reps per site) biomass removal treatments that included: stem only, full-tree, and full-tree + forest floor removal. Routine (every 5 years) measurements have been carried out to track changes in soil carbon and nutrient levels, as well as stand- and individual-tree growth and development metrics and foliar nutrition. The published results from Ontario’s LTSP program, in combination with the North American-wide LTSP synthesis outputs, have suggested that these nutrient-poor, conifer-dominated sites are less sensitive to biomass (nutrient) removals than previously thought. The evidence provided through peer-reviewed publications, conference and workshop presentations, and field tours was substantive and led to a review and revision of the full-tree logging direction within Ontario’s guidelines. We conclude with a set of recommendations (lessons learned) for the successful delivery of any new long-term, interdisciplinary research projects examining the sustainability of forest-management practices.

Download Full-text

Retrospective retrieval of long-term consistent global leaf area index (1981-2011) from combined AVHRR and MODIS data

Journal of Geophysical Research Atmospheres ◽

10.1029/2012jg002084 ◽

2012 ◽

Vol 117 (G4) ◽

pp. n/a-n/a ◽

Cited By ~ 105

Author(s):

Yang Liu ◽

Ronggao Liu ◽

Jing M. Chen

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Area Index ◽

Modis Data

Download Full-text

Canopy Dynamics of Eucalyptus Maculata Hook. I. Distribution and Dynamics of Leaf Populations

Australian Journal of Botany ◽

10.1071/bt9840387 ◽

1984 ◽

Vol 32 (4) ◽

pp. 387 ◽

Cited By ~ 46

Author(s):

EW Pook

Keyword(s):

Water Supply ◽

Leaf Area ◽

Shoot Growth ◽

Temperature Limit ◽

Leaf Fall ◽

Leaf Production ◽

Area Index ◽

Average Size ◽

Non Destructive

The canopy dynamics of a regenerated 16-year-old stand of pole and sapling E. maculata were studied for 2½ years by repetitive non-destructive measurements in tree crowns accessed from a 20 m high scaffold tower. Average canopy leaf area density over a sample plot of 36 m2 was 0.23 m2 m-3 at a leaf area index of 4.3. Some 75% of leaf area was held in the canopies of overstorey eucalypts above 10 m in height. Average size of leaves increased gradually from top to bottom of tree canopies. Foliage production was usually concentrated in the upper crowns of trees where there was a higher proportion of active shoots, more frequent growth flushes and more rapid turnover of leaves than in lower canopy layers. Leaf area in the upper canopy fluctuated widely but increased in the long term, in mid canopy was more or less maintained and in lowest canopy declined. Crops of developing flower buds present on uppermost branches delayed and/or reduced shoot growth. Foliage production occurred in all months of the year. There was a unimodal annual rhythm of growth rate reaching a maximum in summer and a minimum in winter. Variable water supply, however, influenced production to peak in spring, summer or autumn. No shoot growth occurs in E. maculata at Kioloa when daily mean temperature (averaged for weekly intervals) falls below c. 10½C in winter. An upper temperature limit for growth could not be defined. The species apparently lacks dormancy mechanisms. Shoot growth is 'opportunistic' and occurs whenever environmental conditions are favourable. Patterns of leaf production and leaf fall were variable but peaks showed a general synchrony. Leaf fall, however, tended to lag behind leaf production. Leaves of all ages were shed but main losses were from older cohorts. Some 49% (s.d.±18%) of new leaves were lost while still small or immature, mainly during periods of vigorous shoot growth or low water supply. Browse of immature foliage was light. Normal senescence and leaf fall accounted for almost the entire loss of mature foliage.

Download Full-text

Leaf area – sapwood cross-sectional area relationships in repressed stands of lodgepole pine

Canadian Journal of Forest Research ◽

10.1139/x87-036 ◽

1987 ◽

Vol 17 (3) ◽

pp. 205-209 ◽

Cited By ~ 42

Author(s):

M. G. Keane ◽

G. F. Weetman

Keyword(s):

Hydraulic Conductivity ◽

Leaf Area ◽

Wood Density ◽

Lodgepole Pine ◽

Cross Sectional Area ◽

Sectional Area ◽

Cross Sectional ◽

Density Profiles ◽

Individual Tree ◽

Individual Trees

To better understand the phenomenon of growth "stagnation" in high-density lodgepole pine (Pinuscontorta Dougl. ex Loud.), leaf area and its relationship with sapwood cross-sectional area were examined on both an individual tree and stand basis. Leaf areas of individual trees in a 22-year-old stand varied from 30.8 m2 (dominants in stands of low stocking) to 0.05 m2 (suppressed trees in stands of high stocking). Leaf area indices ranged from 13.4 to 2.3 m2 m−2 between low and high stocking levels, respectively. Over the same stocking range, the ratio of leaf area to sapwood cross-sectional area was reduced from 0.3 to 0.15 m2 cm−2. Intraring wood density profiles showed that ovendry density increased from 0.52 to 0.7 g cm−3 and the proportion of early wood decreased over a stocking level range of 6500–109 000 trees/ha. A reduction in hydraulic conductivity in the stems of stagnant trees, suggested by the greater proportion of narrow-diameter tracheids present, may lead to a greater resistance to water transport within the boles of trees from stagnant stands, leading to low leaf areas.

Download Full-text