Thinning of kelp canopy modifies understory assemblages: the importance of canopy density

2014 ◽  
Vol 514 ◽  
pp. 57-70 ◽  
Author(s):  
EB Flukes ◽  
CR Johnson ◽  
JT Wright
Keyword(s):  
Canopy Density ◽  
Kelp Canopy

Spray Volume, Canopy Density, and Other Factors Involved in Thinner Efficacy

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 553d-553
Author(s):  
C.R. Unrath
Keyword(s):  
Tree Height ◽  
Tree Canopy ◽  
Tree Size ◽  
Water Volume ◽  
Canopy Density ◽  
The North ◽  
Run Off ◽  
Tree Canopies ◽  
Average Water ◽  
Water Volumes

Historically, most airblast chemical applications to apple orchards used a single “average” water volume, resulting in variability of coverage with tree size and also the greatest variable in chemical thinning. This coverage variability can be eliminated by properly quantifying the tree canopy, as tree row volume (TRV), and relating that volume to airblast water rate for adequate coverge. Maximum typical tree height, cross-row limb spread, and between-row spacing are used to quantify the TRV. Further refinement is achieved by adjusting the water volume for tree canopy density. The North Carolina TRV model allows a density adjustment from 0.7 gal/1000 ft3 of TRV for young, very open tree canopies to 1.0 gal/1000 ft3 of TRV for large, thick tree canopies to deliver a full dilute application for maximum water application (to the point of run-off). Most dilute pesticide applications use 70% of full dilute to approach the point of drip (pesticide dilute) to not waste chemicals and reduce non-target environmental exposure. From the “chemical load” (i.e., lb/acre) calculated for the pesticide dilute application, the proper chemical load for lower (concentrate) water volumes can be accurately determined. Another significant source of variability is thinner application response is spray distribution to various areas of the tree. This variability is related to tree configuration, light, levels, fruit set, and natural thinning vs. the need for chemical thinning. Required water delivery patterns are a function of tree size, form, spacing, and density, as well as sprayer design (no. of nozzles and fan size). The TRV model, density adjustments, and nozzle patterns to effectively hit the target for uniform crop load will be addressed.

Bigleaf maple seedling establishment and early growth in Douglas-fir forests

1988 ◽  
Vol 18 (10) ◽  
pp. 1226-1233 ◽  
Author(s):  
Jeremy S. Fried ◽  
John C. Tappeiner II ◽  
David E. Hibbs
Keyword(s):  
Seed Predation ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Early Growth ◽  
Douglas Fir ◽  
Stand Development ◽  
Size Distributions ◽  
Canopy Density ◽  
Successful Establishment ◽  
Survival Of Seedlings

Survival, age and height distributions, and stocking of bigleaf maple (Acermacrophyllum Pursh) seedlings were studied in 1- to 250-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Oregon to identify the stages in stand development in which bigleaf maple is most likely to establish successfully from seed. Maple seedling emergence averaged 30–40% where seeds were planted and protected from rodents but was typically <2% for unprotected seeds. Seedling survival after 2 years was highly dependent on canopy density, measured by percent sky. Average 1st-year survival of seedlings originating from planted, protected seeds was highest in clearcuts (1–2 years old, 36% survival, 56% sky) and pole-size stands (41–80 years old, 30% survival, 17% sky) with sparse understories and canopies. It was lowest in young stands with dense canopies (20–40 years old, 4% survival, 8% sky) and old stands (81–250 years old, 14% survival, 13% sky) with dense understories. Naturally regenerated populations of bigleaf maple seedlings, which occurred in aggregations (0.005–0.04 ha in area), were most abundant (up to 10 000/ha) in pole-size Douglas-fir stands. Although seedling size distributions within stands had a strongly inverse J shaped form, size distributions within aggregations appeared more normal (bell-shaped). Seedling age rarely exceeded 15 years. Seedlings grew slowly in the understory, often reaching only 25 cm in height after 8–10 years, and were intensively browsed by deer. Naturally regenerated seedlings were virtually absent from clearcuts, probably because of dense competing vegetation and lack of seed caused by poor dispersal and seed predation. The "window" for the most successful establishment of bigleaf maple seedlings appears to begin after canopy thinning and end before forbs and shrubs invade.

Influence de la densité du couvert forestier sur le développement architectural de jeunes chênes sessiles, Quercus petraea (Matt.) Liebl. (Fagaceae), en régénération forestière

2000 ◽  
Vol 78 (12) ◽  
pp. 1531-1544 ◽  
Author(s):  
Eric Nicolini ◽  
Daniel Barthélémy ◽  
Patrick Heuret
Keyword(s):  
Quercus Petraea ◽  
Growth Unit ◽  
Growth Morphology ◽  
Basal Diameter ◽  
Canopy Density ◽  
Sessile Oak ◽  
The North ◽  
Oak Trees ◽  
Branching Patterns ◽  
Number Of Branches

The growth and branching patterns of the main axis of 6-year-old sessile oak, growing in a natural regeneration in the north of France, were analysed each year retrospectively according to three increasing canopy density conditions: large gap, small gap, and dense canopy. Increasing gap size is associated with an increase in the total height, basal diameter, branching probability, and global polycyclism rate of the trees. At the growth unit or annual shoot level, from dense canopy to large gaps these botanical entities also show an increase in their total length, number of nodes, polycyclism, and branching rate as well as mean number of branches and mean internode length. A discussion of our results revealed some endogenous features of growth and branching patterns in young sessile oak trees. It is also shown that increasing canopy density generally tends to reduce the expression of the endogenous architectural sequence of differentiation of young sessile oak trees. Young trees growing below dense canopy thus seem to be "delayed" in their sequence of differentiation and appear to be in a "waiting" status, whereas young trees growing in large gaps exhibit an architecture very similar to trees growing in nurseries under nonlimiting growth conditions.Key words: architecture, Quercus petraea, growth, morphology, canopy density.

Structure and Regeneration of Sal (Shorea robusta Gaertn. f.) Forests in Shiwalik Region of Kumaun Himalaya, India

2017 ◽  
Vol 40 (1) ◽  
pp. 1-8
Author(s):  
Bhawna Adhikari ◽  
◽  
Bhawana Kapkoti ◽  
Neelu Lodhiyal ◽  
L.S. Lodhiyal ◽  
...  
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Tree Canopy ◽  
Canopy Density ◽  
Kumaun Himalaya ◽  
Shorea Robusta ◽  
Canopy Trees ◽  
Dense Forest ◽  
Open Forest ◽  
Sal Forest

Present study was carried out to assess the structure and regeneration of Sal forests in Shiwalik region of Kumaun Himalaya. Vegetation analysis and tree canopy density was determined by using quadrat and densitometer, respectively. Density of seedlings, saplings and trees was 490-14067, 37-1233, and 273-863 ind.ha-1 respectively. The basal area was 0.12-5.44 m2 ha-1 reported for saplings and 25.4-77.6 m2 ha-1 for trees. Regeneration of Sal was found good in Sal mixed dense forest followed by Sal open forest and Sal dense forest, respectively. Regeneration of Sal was assisted by the presence of associated tree species as well as the sufficient sunlight availability on ground due to adequate opening of canopy trees in Sal forest. Thus it is concluded that the density of tree canopy, sunlight availability and also associated tree species impacted the regeneration of Sal in the region.

Use of roadside remnants of softwood scrub vegetation by birds in south-eastern Queensland

1993 ◽  
Vol 20 (2) ◽  
pp. 233 ◽  
Author(s):  
GJ Leach ◽  
HF Recher
Keyword(s):  
Management Practices ◽  
Bird Community ◽  
Vegetation Diversity ◽  
Minimum Width ◽  
Canopy Density ◽  
South Eastern ◽  
Roadside Vegetation ◽  
Length Width ◽  
Tree Component

Birds in roadside and remnant patches of vegetation in the Marburg district of south-eastern Queensland were studied from November 1989 to February 1990. Effects of the length, width and height of the tree, shrub and herb layers, and their major components, on the bird community were determined. In all, 43 species of birds were observed in roadside vegetation; 16 of these were abundant and widely distributed. Silvereyes were most frequently observed (240 observations), followed by superb fairy-wrens (59), yellow thornbills (53), double-barred finches (26), red-backed fairy-wrens (25) and Lewin's honeyeaters (20). Apart from silvereyes (20-654 of observations), and superb fairy-wrens on two roads (12 and 13%) and yellow thornbills on one (15%), no other species constituted more than 10% of observations on any road. In all, 48 species of birds were observed in remnant patches of vegetation, 14 in all of them. Rates of detection in remnant patches ranged from 2.7 to 5.3 birds per 5 min compared with a mean maximum rate for roadside vegetation of 1.3. The richness of the roadside avifauna increased significantly (P=0.001) as the volume (length x width x height) of the tree component, especially the softwood species, increased. The diversity of tree species in softwood remnants and the greater canopy density appear to be important factors that enhance the bird community. The number of birds was also correlated (P=0.05) with the volume of brigalow, Acacia harpophylla. The correlation of the volume of woody weeddshrubs with the number of birds was low (P=0.05), and with the number of species not significant, even though woody weeds were a major component of roadside vegetation. Although supporting fewer birds than remnant patches of vegetation, roadside vegetation contributes importantly to conservation of the avifauna in the Marburg district. Some simple management practices, such as maintaining a minimum width of undisturbed vegetation and retaining vegetation diversity, would ensure or enhance the long-term conservation benefits. Opportunities to regenerate softwood remnants could also be taken, particularly to enhance the value, and possibly prolong the life, of the associated remnants of brigalow.

Ground deposit of pesticides in relation to the cereal canopy density

1999 ◽  
Vol 55 (12) ◽  
pp. 1210-1216 ◽  
Author(s):  
Steen Gyldenkaerne ◽  
Bo J M Secher ◽  
Ebbe Nordbo
Keyword(s):  
Canopy Density

scholarly journals The effect of nitrogen supply on specific yield and fruit quality of apple (Malus domestica Borkh.)

2005 ◽  
Vol 11 (2) ◽  
Author(s):  
J. Racskó ◽  
J. Nagy ◽  
Z. Soltész ◽  
M. Soltész ◽  
P. T. Nagy ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Dry Matter ◽  
Shape Index ◽  
Matter Content ◽  
Nitrogen Supply ◽  
Specific Yield ◽  
Dry Matter Content ◽  
Canopy Density ◽  
Apple Cultivars

The aim of the present study was to determine the effect of nitrogen supply on yield and fruit quality of apple cultivars and to explore the relationships between canopy density and the different fruit quality parameters. The experiments were carried out at Kálmánháza, in Eastern Hungary in a private orchard in 2003-2004. The response of four apple cultivars ('Elstar', 'Gala Prince', 'Granny Smith', 'Idared') to different nitrogen dosages was studied. The assessed and calculated indices were: yield, fruit diameter, fruit height, shape index, fruit mass, firmness, dry matter content and colouration. The results indicated that nitrogen fertilization has a significant effect on the yield and fruit quality of apple cultivars. The calculated specific yield values were reduced by the application of nitrogen via the increase in the volume of the canopy. An opposit trend was observed for fruit diameter, fruit height and fruit weight, which increased with increasing nitrogen supply. The reduced shape index caused flattening of fruits. However, the improvement of fruit quality via increasing nitrogen dosage is only virtual, since these dosages increase the fruit size, but firmness, dry matter content and colouration are diminished, which decreases the value of the fruits on the market. The authors also studied the relationships between canopy density responsible for assimilation and light supply of the fruits and the different fruit quality parameters. The closest linear inversely proportional relationship was found in the case of colouration. There was a negative linear relationship between canopy density and firmness or dry matter content. The relationship between canopy density and fruit mass could be described by a quadratic polinomial function.

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