EXAMPLE 



Table 1 . An orchard with 400 mature Delicious apple trees received overwinter depredation by deer. Data 

 collected from trees necessary to determine impact of depredation on fruit production for the first crop 

 following depredation. 



- 1,600 bushels were harvested and sold @ $8/bu or $6 net profit 



- apples harvested within browsing zone = 1,600 x 23.4% = 374.4 bu 



- percent of potential production harvested within the browsing zone = 100.0% - 16.2% loss = 83.3% 



- therefore, 374.4 bu harvested / 0.838 = 446.8 bu potentially harvestable if depredation had not occurred 



- net loss = 446.8 - 374.4 = 72.4 bu lost to depredation 



- value = 72.4 bu x $6 per bu = $434.40 



tive trees in the orchard. If more than one cultivar is 

 present, select 15 trees per cultivar. 



2. Select two major branches on opposite sides of the 

 main trunk but within the browsing reach of deer (ap- 

 proximately 6 ft). On small trees, use the entire tree. 

 Beginning at the main trunk, follow the branch along 

 smaller and smaller branches to the end. At each 

 junction, select the larger branch and continue follow- 

 ing it within the browsing zone. Record all intact and 

 all nipped buds (terminal buds of the current year's 

 growth and all buds along second year or older stems 

 where those buds protrude greater than 1 cm in 

 length). 



3. Calculate the mean percentage of bud removal as: 



total nips / (total buds + total nips) 

 Then determine the mean for all 15 trees combined. 



4. Estimate the proportion of trees within browsing 

 reach of deer. This is most easily done when trees are 

 in the early bloom stage. Randomly select 15 trees of 

 each cultivar (although it is suggested that the same 

 trees used in the nip counts be used, it is not necessary). 

 Mark each tree with plastic flagging around the trunk 

 at browsing height (about 6 ft); if browsing extends 

 below or above 6 ft overall, adjust height accordingly 

 but browsing height must be consistent among all 15 



24 



Fruit Notes, Summer, 1990 



