158 



Garden and Forest. 



[March 26, 1890, 



situations. Throughout the area covered by its natural distri- 

 bution there are millions of acres adapted to the highest de- 

 velopment of the Hemlock, which are unfit for any other than 

 forestal purposes. No requirements exist, therefore, in regard 

 to soil and climate, which are not amply supplied. 



II. — The tendency of the Hemlock to renew itself naturally 

 on areas which have been largely or complely deforested, is 

 less marked than that of most other tree species. Still, the 

 tendency to natural renewal is by no means wanting. The 

 writer has seen a large pasture adjacent to a piece of Hem- 

 lock woods well stocked with a growth of young Hemlocks. 

 They bore evidence of having been disturbed by cattle, but 

 there were abundant indications that if left to themselves they 

 would completely reforest the area on which they were grow- 

 ing. Other similar instances have been mentioned by corre- 

 spondents in numerous locations. The Hemlock is an abun- 

 dant bearer when once it has reached the fruiting age, although 

 the seed-crops are biennial. The chances for a wide dispersal 

 are enhanced by the structure and hygroscopic quality of the 

 cone. The seeds are shed at different periods, extending from 

 autumn until spring. Fertile seeds have been found in the 

 cones as late as the last of April. The seeds, if favorably 

 placed, germinate freely ; the specially favoring conditions 

 being a moderate amount of shade and moisture. The lati- 

 tude, in this respect, is not great, as any considerable excess 

 of moisture causes the young plants to damp off, while 

 from any great lack of it they wither and perish. While the 

 young plants must be regarded as exceedingly delicate, they 

 are, nevertheless, capable of enduring a considerable range 

 of climatic and other conditions. There seems to be no in- 

 herent reason in the nature and constitution of the Hemloqk 

 to operate against its natural renewal on areas from which it 

 has been removed, provided the conditions are favorable to 

 that end. The essential conditions are twofold : First, the 

 rigid exclusion of all domestic animals ; second, obviously 

 and chiefly, the prevention of forest fires. While these con- 

 ditions apply to all tree species in common with the Hemlock, 

 they are relatively of greater importance in regard to the latter 

 on account of its constitutional delicacy. A third condition would 

 be the removal of a certain proportion of the seedlings of other 

 species which are endowed with a greater degree of vigor. 



III. — In regard to the cultivation of 

 Hemlock in nursery rows for subse- 

 quent transplanting, practical experience 

 shows its want of adaptation to this pur- 

 pose. In its seedling state it is probable 

 that no other tree species is of so slow 

 growth ; at the end of its first year a 

 seedling is rarely more than an inch in 

 height ; and at the end of its third or 

 fourth year it has increased to scarcely 

 more than three or four inches. This 

 low growth is characteristic of the Hem- 

 lock during many subsequent years, 

 although at a later period the relative rap- 

 idity of growth is somewhat increased. 

 While these facts materially lessen the 

 adaptability of the Hemlock to forestal 

 purposes, they do not prevent the em- 

 ployment of the Hemlock in the renewal 

 of forests in the method previously con- 

 sidered. Moreover, it should be stated 

 that while the rate of growth here in- 

 dicated is based upon my own experi- 

 ence and observation, and is confirmed 

 by many correspondents who have had 

 large experience in the cultivation of the Hemlock, there are 

 a few correspondents who consider it to be, in specially 

 favored situations, as rapid a grower as most other conifers. 



IV. — A few facts concerning the consumption of the pro- 

 ducts of the Hemlock may be here noted. What are regarded 

 as trustworthy estimates, place the amount of bark used for 

 tanning purposes in 1887 at 1,200,000 tons, which, at eight 

 dollars per ton, would represent a value of $9,600,000. 

 Estimating the amount of manufactured lumber at 1,500 feet 

 per ton of bark, would give 1,800,000,000 feet as the total 

 amount, representing a value, at twelve dollars per 1,000 feet, 

 of $21,600,000. While a considerable portion of the peeled 

 timber is wasted, and should be deducted from the above 

 estimates, it is believed this amount is made good by the use 

 of unpeeled timber for railway ties, fuel and various other 

 purposes. It may, therefore, be estimated that the full value 

 of the products of the Hemlock is, in round numbers, $30,000,- 

 000 per annum. The length of time during which our 

 remaining Hemlock forests will continue with this annual 



Fig. 29. — Seedling Hem- 

 locks, one and three years 

 old, natural size. 



drain upon them is, of course, uncertain ; but the most care- 

 ful and conservative observers consider that the present 

 supply could not be maintained for a period exceeding twenty 

 or twenty-live years. It becomes, therefore, a question of 

 great practical importance as to the way in which the existing 

 demands upon the Hemlock shall be hereafter supplied. 

 These supplies can, of course, be afforded in only two ways : 

 First, by the substitution of corresponding products from other 

 trees or other sources ; Second, by the renewal of the Hemlock 

 forests. 



The general conclusions which have been arrived at as the 

 result of a somewhat careful investigation of the present 

 subject may be briefly summed up as follows : The Hemlock 

 has been, from the earliest settlement of the country, a tree of 

 vast economic importance to the people of the eastern and 

 northern states ; that in this respect it has been second to 

 none of our native forest trees, with a possible exception of 

 the White Pine ; that the tree has been exhausted from vast 

 areas where it formerly existed in great abundance ; that at 

 the present rate of consumption the entii'e supply will be 

 practically exhausted in from twenty to thirty years ; that 

 nothing has been anywhere done toward reforesting the 

 areas from which it has been removed, and that its nature 

 and constitution afford only a moderate promise of its adapta- 

 tion to economic forestal purposes. Finally, it may be stated 

 that the most prominent result of the investigation to which 

 I have referred has been to give great emphasis to the fact, 

 not as yet sufficiently recognized, that the country ought to 

 give prompt and energetic attention to the whole subject of 

 forestry, that no successful forestal management is possible in 

 the absence of adequate knowledge of the subject, and that 

 this knowledge is attainable only through intelligent experi- 

 ment, experience and study. — Read before the Americati For- 

 estry Association by Professor A. N. Prentiss. 



Correspondence. 



Hollyhock Diseases. 

 To the Editor of Garden and Forest : 



Sir. — So much has been said about the true Hollyhock dis- 

 ease (Puccinia malvacearum, Mont.) that it is only fair to call 

 attention to another one. Last year, in and around New 

 Brunswick, New Jersey, it was almost impossible to find a 

 single healthy Hollyhock among the thousands of plants. At 

 first the lower leaves began to exhibit large circular brown 

 patches, sometimes bounded upon the side toward the centre 

 of the leaf by the veins, thus giving an angular outline. Soon 

 after the largest leaves of all suffered and fell, and by the mid- 

 dle of August whole rows of the plants exhibited leafless 

 stems. Few gardeners now have any plants, but one enterpris- 

 ing propagator has a long row of fair-sized seedlings in pots. 

 When I first saw these seedlings they were- — a few hundred of 

 them — in a box under sash, and so badly infected with the 

 blight that there seemed at first to be no hope for them. Per- 

 haps one plant in five was saved and pricked out in a fresh 

 box ; and the following remedy was applied almost daily : 

 Three ounces of carbonate of copper were dissolved in a 

 quart of standard ammonia, and afterward diluted to twenty- 

 two gallons with water. At the same time the older leaves 

 which developed the spots were removed and burned, until a 

 comparatively healthy condition has been reached. The dis- 

 ease is due to a Cercospora and probably C. althceina, Sacc, 

 a species which in its various forms grows upon the common 

 Mallow (Ma/va rotundifolia), Velvet-leaf {Abutilon Avicennce) 

 and a species of Callirhoe. 



As said in the beginning, too much credit should not be 

 given to the Hollyhock rust {P. malvacearum) that has come 

 to us from abroad while we have a blight of our own to attend 

 to, even if it is one that can be kept in check perhaps if taken 

 in time by using a compound of copper. 



Rutgers College. Byron D. Halsted. 



Grafting. 



To the Editor of Garden and Forest : 



Sir. — I do not think Mr.Parsons goes quite to the bottom of this 

 question of grafting (see p. 44). My view of the question is 

 that if any conifer will not grow in America or in Europe with- 

 out grafting, it is not worth cultivation at all. Grafting for 

 timber-trees will never pay. The plain fact is that own-rooted 

 fruit-trees have never, or very, very rarely, been tried side by 

 side with the grafted ones, and until this is done no one really can 

 know that grafting is the best, or even one of the best ways. 

 One would have thought that our horticultural societies, or 

 those botanists who profess to know something of vegetable 



