Laser, ultrasonic and manual measurements of citrus tree canopy volume

2001 ◽  
Author(s):  
S. D. Tumbo ◽  
M. Salyani ◽  
J. D. Whitney ◽  
T. A. Wheaton ◽  
W. M. Miller
2021 ◽  
Vol 64 (5) ◽  
pp. 1611-1624
Author(s):  
Worasit Sangjan ◽  
Sindhuja Sankaran

HighlightsTree canopy architecture traits are associated with its productivity and management.Understanding these traits is important for both precision agriculture and phenomics applications.Remote sensing platforms (satellite, UAV, etc.) and multiple approaches (SfM, LiDAR) have been used to assess these traits.3D reconstruction of tree canopies allows the measurement of tree height, crown area, and canopy volume.Abstract. Tree canopy architecture is associated with light use efficiency and thus productivity. Given the modern training systems in orchard tree fruit systems, modification of tree architecture is becoming important for easier management of crops (e.g., pruning, thinning, chemical application, harvesting, etc.) while maintaining fruit quality and quantity. Similarly, in forest environments, architecture can influence the competitiveness and balance between tree species in the ecosystem. This article reviews the literature related to sensing approaches used for assessing architecture traits and the factors that influence such evaluation processes. Digital imagery integrated with structure from motion analysis and both terrestrial and aerial light detection and ranging (LiDAR) systems have been commonly used. In addition, satellite imagery and other techniques have been explored. Some of the major findings and some critical considerations for such measurement methods are summarized here. Keywords: Canopy volume, LiDAR system, Structure from motion, Tree height, UAV.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1462
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan

Citrus yields have declined by almost 56% since Huanglongbing (HLB) was first found in Florida (2005). That reduction forced citrus growers to replant trees at much higher densities to counter-balance tree loss. The current project aims to determine how much water is required to grow citrus trees at higher planting densities without reducing their productivity. The study was initiated in November 2017 on eight-month-old sweet orange (Citrus sinensis) trees grafted on the ‘US-897′ (Cleopatra mandarin × Flying Dragon trifoliate orange) citrus rootstock planted in the University of Florida, Southwest Florida Research and Education Center (SWFREC) demonstration grove, in Immokalee, FL (lat. 26.42° N, long. 81.42° W). The soil in the grove is Immokalee fine sand (Sandy, siliceous, hyperthermic Arenic Alaquods). The demonstration grove included three densities on two rows of beds (447, 598, and 745 trees per ha) replicated four times each and three densities of three rows of beds (512, 717, 897 trees per ha) replicated six times. Each density treatment was irrigated at one of two irrigation rates (62% or 100%) during the first 15 months (2017–2019) then adjusted (2019–2020) to represent 26.5, 40.5, 53, and 81% based on recommended young citrus trees evapotranspiration (ETc). Tree growth measurements including trunk diameter, height, canopy volume, leaf area, and root development were evaluated. During the first year, reducing the irrigation rate from 100% to 62% ETc did not significantly reduce the young citrus tree growth. Conversely, the lower irrigation rate (62% ETc) had increased citrus tree’s leaf area, canopy volume and tree heights, root lifespan, and root length by 4, 9, 1, 2, and 24% compared with the higher irrigation rate (100%), respectively. Furthermore, the root lifespan was promoted by increasing planting density. For instance, the average root lifespan increased by 12% when planting density increased from 447 to 897 trees per ha, indicating that planting young trees much closer to each other enhanced the root’s longevity. However, when treatments were adjusted from April 2019 through June 2020, results changed. Increasing the irrigation rate from 26.5% to 81% ETc significantly enhanced the young citrus tree growth by increasing citrus tree’s canopy volume (four fold), tree heights (29%), root lifespan (86%), and root length (two fold), respectively. Thus, the application of 81% ETc irrigation rate in commercial citrus groves is more efficient for trees from two to four years of age.


1999 ◽  
Vol 18 (3) ◽  
pp. 109-115 ◽  
Author(s):  
A. K. Alva ◽  
O. Prakash ◽  
Ali Fares ◽  
Arthur G. Hornsby

1986 ◽  
Vol 26 (5) ◽  
pp. 619
Author(s):  
KR Chapman ◽  
B Paxton ◽  
DH Maggs

Five processing guava clones (GA6- 1, GA7- 12, GA8-30, GA9-35, GA11-56) were tested over 3 cropping years at Nambour, in coastal south-eastern Queensland. Mean marketable yield for the first crop at 2 years of age was 45 kg/tree or 36.23 t/ha at a density of 805 trees/ha. GA11-56, the most acceptable clone for processing, also gave the highest marketable yields of 627, 71.65 and 72.53 t/ha for the first 3 crops. Yield per unit cross sectional area of trunk was a more simple and useful index of yield efficiency than more complex parameters including a fruitfulness index and multiple regressions with yield of north-south canopy spread, number of primary branches and combinations of these and trunk girth. Similarly, trunk - - girth provided at least as good an estimate of tree size as the vigour index. Tree dimension measurements which included east-west canopy spread, north-south canopy spread, tree height, stem height, number of primary branches, crown height, crown radius, tree canopy volume, canopy surface area and an index of crown weight provided no consistent indication of tree size. They were not highly correlated with either accumulated or final yield of the guava. The GA11-56 clone because of its yield, fruit size and other desirable processing characteristics was the only clone that could be recommended for commercial plantings.


HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1859-1865 ◽  
Author(s):  
Kirandeep K. Mann ◽  
Arnold W. Schumann ◽  
Thomas A. Obreza ◽  
Jerry B. Sartain

Citrus production in Florida is commonly affected by a high degree of spatial variability of soils. Therefore, this study developed rapid indicator crop bioassays to evaluate the relationships between indicator crops and citrus production at various soil depths. A citrus grove was divided into five productivity zones based on existing tree canopy volume using GIS software (“very poor,” “poor,” “medium,” “good,” and “very good”). Visual ratings of percentage cover were collected from each zone using a 1-m2 quadrant. Six random soil samples were collected between the tree rows from each productivity zone at four depths (0 to 15, 15 to 30, 30 to 45, and 45 to 60 cm). Greenhouse bioassay experiments used sorghum and radish crops grown in soil sampled from four depths. Overhead photographs of potted radish plants were captured periodically with a SLR digital camera to calculate leaf area by image processing. Shoot weights, shoot length, root weights, and leaf nutrient concentrations were measured at harvest (56 and 21 days after germination for sorghum and radish, respectively). Germination, shoot length, and shoot weight of sorghum and radish were significantly affected by the productivity zone. Sorghum (0 to 30 cm), radish (0 to 45 and 0 to 60 cm) and weed cover were strongly correlated (r ≈0.50 to 0.60***) with citrus yield and canopy volume at the lower two depths. The strong relationships (r > 0.50***) of sorghum and radish shoot weights and weed cover with soil properties at greater depths demonstrated the important role of cumulative root zone depth of 60 cm in differentiating citrus productivity. These results revealed that citrus production in poor areas of the grove was limited by the shallow depth of productive soil, and citrus productivity could be successfully mapped using indicator crop bioassays with soil samples taken at multiple depths.


HortScience ◽  
1997 ◽  
Vol 32 (6) ◽  
pp. 1059-1160 ◽  
Author(s):  
Y.C. Li ◽  
A.K. Alva ◽  
D.V. Calvert ◽  
M. Zhang

It is generally believed that the interception of rain by the citrus tree canopy can substantially decrease the throughfall under the canopy as compared to that along the dripline or outside the canopy (incident rainfall). Therefore, the position of placement of soil-applied agrichemicals in relation to the tree canopy may be an important consideration to minimize their leaching during rain events. In this study, the distributions of rainfall under the tree canopies of three citrus cultivars, `Marsh' grapefruit (Citrus paradisi Macf.), `Hamlin' orange (Citrus sinensis L. Osbeck), and `Temple' orange (Citrus hybrid), were evaluated at four directions (north, south, east, west), two positions (dripline and under the canopy), and stem flow. There was not a significant canopy effect on rainfall amounts from stem flow or dripline, compared with outside canopy, for any citrus cultivar or storm event. However, throughfall varied significantly among the four cardinal directions under the canopy of all three citrus cultivars and was highly related to the wind direction. Among the three citrus cultivars evaluated in this study, throughfall, stem flow, and canopy interception accounted for 89.5% to 92.7%, 0.5% to 4.7%, and 5.8% to 9.3% of the incident rainfall, respectively.


2002 ◽  
Vol 42 (4) ◽  
pp. 503 ◽  
Author(s):  
R. J. Nissen ◽  
A. P. George

Five methods of controlling tree size, viz. growth retardant (foliar-sprayed and trunk-injected paclobutrazol), root-restriction bags, cherimoya rootstock and sugar apple (Annona squamosa) interstock, were evaluated for their effects on growth, yield and fruit quality of custard apple (Annona spp. hybrid cv. African Pride) in subtropical Australia. Compared with trees on their own roots, sugar apple interstock was highly effective in dwarfing 'African Pride' trees, reducing tree canopy volume by 72-90%. Root-restriction bags (woven fibreglass) proved to be only partially effective in controlling tree size due to growth of major roots through the seams. Compared with trees on their own roots, cherimoya rootstock alone, and sugar apple interstock increased fruit weight per unit canopy volume by a maximum of 3- and 5-fold, respectively. Sugar apple interstock reduced the severity of fruit disorders 'woodiness' and 'brown pulp' by about 75 and 50%, respectively.


2006 ◽  
Vol 16 (2) ◽  
pp. 339-344 ◽  
Author(s):  
Q.U. Zaman ◽  
A.W. Schumann ◽  
H.K. Hostler

Many citrus groves in Florida were affected by hurricanes in Summer 2004. A commercial 42-acre `Valencia' sweet orange (Citrus sinensis) grove of 2980 trees was routinely scanned with an automated ultrasonic system to measure and map tree canopy volumes. We estimated tree damage by comparing canopy volumes measured before and after the hurricanes of 2004. Ultrasonically sensed tree canopy volume was mapped and the relative tree canopy volume loss percentage (TCVL%) for each tree was calculated and classified into six categories [≤0 (no damage), 1% to 24%, 25% to 49%, 50% to 74%, 75% to 99%, and 100%]. Authenticity of the ultrasonically sensed missing trees was established by ground truthing or matching visually observed and georeferenced missing tree locations with ultrasonically sensed missing trees in the grove. Ninety-one trees were found missing during ground inspections after hurricanes and they exactly matched with ultrasonically sensed missing tree locations throughout the grove. All of the missing trees were in TCVL% categories 5 and 6 (≥75% damage). Some canopy volume was still detected with ultrasonics at the missing tree locations because of the presence of tall grass, weeds, or branches of large adjacent trees. More than 50% of trees in the grove were damaged (completely or partially) and generally larger trees (>100 m3) were damaged more by the hurricanes than small or medium size trees in each tree canopy volume loss category. The automated ultrasonic system could be used to rapidly identify missing trees (completely damaged) and to estimate partial tree canopy volume loss after hurricanes.


2019 ◽  
Vol 27 (1) ◽  
pp. 1-10
Author(s):  
Augustyn Mika ◽  
Zbigniew Buler ◽  
Jacek Rabcewicz ◽  
Paweł Białkowski ◽  
Dorota Konopacka

AbstractTwo plum cultivars ‘Record’ and ‘Empress’ and one prune cultivar ‘Common Prune’ were planted in spring 2014, spaced at 4.5 × 1.5 × 2.0 m, to be trained to the “Y”- and “V”-trellising systems for mechanical harvesting of dessert fruits with a canopy-contact harvester. The applied trellising systems were compared with the standard central leader system at the same spacing. Trellised trees showed a tendency to grow less well than leader-trained trees, but during the four years of training, they created a higher canopy volume than the control trees because of their spreading form. Trellised trees were able to give yields comparable to those of standard trees. Light distribution within the tree canopy was acceptable in all the training systems. After 4 years of training, the trees were suitable for mechanical harvesting. The effectiveness of mechanical harvesting varied from 85% to 90%. The quality of the fruits harvested with a canopy-contact harvester was comparable to that of manually picked fruits. The consumption of quality of fruits after mechanical harvesting rated on a 5-grade scale was 0.5 grade lower than that of manually harvested fruits. These fruits were acceptable in the local fruit market. Mechanical harvesting was 10–30 times faster compared to manual picking. The cost of the trellising system calculated per 1 ha was 2.0 times higher than that of the standard system.


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