AFFORESTATION IN THE UNITED KINGDOM 631 



greater depth, seems to prove a balance capacity for consuming 

 water. This is of the greatest importance, as it provides a 

 means of reclaiming swampy land, of which there is much in 

 the United Kingdom, particularly in Ireland. Again, where the 

 rainfall is irregular or periodically scarce, the retarding of 

 drainage by the trees themselves, the litter and undergrowth 

 and the penetration of the soil facilitated by the loosening effect 

 of the roots prolong the benefits of precipitation ; this is par- 

 ticularly the case in hilly country where otherwise the drainage 

 is rapid. 



Other, and often very important, purposes for which forests 

 are grown are the prevention of erosion, land-slips, and the 

 silting-up of rivers and lowlands. This is due to the influence 

 of forest on drainage and the stability afforded by the roots of 

 trees. Although there may not be any great cause as yet for 

 afforestation in Great Britain or Ireland on this account, yet 

 instances are not wanting in which great havoc or more 

 expensive and unproductive works might have been avoided 

 had trees been planted. 



The value of the protection from wind afforded by forest 

 is generally admitted, and the purity of the forest air and the 

 larger quantity of ozone it contains are advantages which 

 cannot be overlooked in considering the benefit to all who 

 work in or visit the forests, for unhealthy conditions associated 

 with the greater relative humidity of the atmosphere do not 

 arise in the temperate climate of the United Kingdom. 



PART III 



The steady progress of opinion, from a desire to improve 

 the condition of existing forests to the development of schemes 

 for their extension, is strikingly illustrated in the findings of 

 successive committees. The chief reasons for the need of more 

 extended forests have been recapitulated ; it is proposed now 

 to describe how practical progress can best be made. 



It is natural to inquire the reasons for the unsatisfactory 

 conditions of so many of the forests, as this is advanced by 

 many, who have not thoroughly studied the question, as 

 indicating probable failure of any attempts at further afforesta- 

 tion. The reasons are many. In the first place the rapidly 

 increasing demand for timber before the development of means 

 of communication placed supplies from other countries at 



