58 



THE CANADIAN HORTICULTURIST. 



of the sap on the sides of the tree most ex- 

 posed to the sun. Very often there are warm 

 days during- the month of March and the sun 

 shining on the trunk of the tree thaws the 

 sap, A severe frost at night freezes it up 

 ag-ain and this may occur several times. 

 This alternate thawing and freezing either 

 separates the bark and the cambium from 

 the trunk of the tree or injures the wood 

 tissues so much that growth is prevented 

 and these parts die. If the tree is badly 

 sunscalded it is so weakened that it dies be- 

 fore the wound can heal over, or very fre- 

 quently the same season. 



Prevention. This injury may be prevented 

 to a large extent by only planting trees which 

 are headed low, thus exposing but a short 

 trunk to the rays of the sun ; also by inclining 

 the young trees somewhat to the south when 

 planting, thus preventing the sun's rays 

 striking the trunk except for a short time. 

 Where the trees have been planted and are 

 liable to become sunscalded, the trunks may 

 be protected by using a veneer of wood 

 which encircles the trees, thus preventing 

 the rays of the sun from striking the trunk. 

 It should be loose so that there will be an 

 air space between it and the tree. The ends 

 of it can be fastened together by means of 

 wire or twine. Another protector is made of 

 finely meshed galvanized iron netting which 

 is more permanent than the wooden protect- 

 or. In outlying districts where these pro- 

 tectors cannot be purchased, a good substi- 

 tute may be made out of birch bark. 

 Building paper tied around the tree is also 

 useful. All of these protectors are effective 

 in preventing the ravages of mice. Corn- 

 stalks, boards, and many other things may 



be used to protect the tree from sunscald. 

 Nothing, however, that will be likely to har- 

 bor mice should be used. These protectors 

 should be put on in the autumn. When a 

 tree has been injured by sunscald the injured 

 parts should be carefully cleaned away and 

 the wound covered with grafting wax or 

 paint. If the tree is young and likely to 

 suffer, it should be protected in the manner 

 described above. 



The tree protectors used at the Central 

 Experimental Farm are made of elm. They 

 are of two sizes, one kind being thirty inches 

 long and twelve inches wide, and the other 

 twenty inches long and eleven inches wide, 

 and have proved very satisfactory in preven- 

 ting sunscald and injury from mice. They 

 were procured in Minnesota and Kansas and 

 are sold at Jft6.oo per thousand, although I 

 have been informed they can be obtained for 

 less. 



There is another form of sunscald which 

 appears to be a summer scald. When the 

 weather is very hot in summer large limbs, 

 which are exposed, are often scalded ap- 

 parently by the fierce heat. This probably 

 occurrs most frequently when there is not a 

 good circulation of sap in the tree and when 

 the tree is making very little growth. It 

 also often occurs after too severe pruning. 

 Limbs which have been protected by the 

 foliage from other limbs are suddenly laid 

 bare after heavy pruning. The bark on 

 these limbs is not as tough as that of limbs 

 which have always been exposed to the 

 weather and it cannot withstand the heat of 

 the sun and sunscald occurs. Hence, trees 

 should be kept vigorous and pruning be 

 done very carefully. 



