Resume Introduction The growing field of our object trees

Resume Introduction The growing field of our object trees is also a field in which the weeds which have in three so that, of trees And the growth of grow. In these fields there are our severe fightings against weeds, been successive from older times, and will be far into the future. As WILLIS pointed important without excluding Weed ways under the competition out, weeds cause and water damage and to cultivated light the normal nitrogen capture trees growth interception, in Fig. 1-1. the of weeds, we can not except the aid of human control, at least hands, as shown by the author is called " Weed Control." means the in forestry, of these competitions promoting planted trees by the excluding or reducing the competition between weeds and trees by physical and chemical means, and never means the complete removal of weeds. In this paper, it is defined that a weed is a plant which therefore ennial at the damages undesirable, plants same in the forest and the nursery. in nursery, time with annual our or perennial object is not useful, and Such as annual or per weeds, ferns, shrubs, and trees, vines and mistletoes in forest stand, the all plants useful trees, are weeds. 1. Influences of Weeds which exist in the same place and trees, give, more or less, some to cultivated Chapter upon Forest Trees 1. Interception Reduction The degree Kumamoto of Light by Weeds intensity caused by weeds : Weeds grow with trees in the crops—trees by interception. and the kinds of weeds. on the foot of Mt. Aso in and horizontal herbal plots (Artemisia extents. in which princeps are 50 °o of light forest and for 6 or 7 years they damage our objective of interception were is due to the amount various Two surveys done under decrease sinensis which herbage Pref., to know the interception as to vertical Fig. 1-3 shows the vertical grow Susuki (Miscanthus PAMPANINI). Each similar, relative are not dark curve intensity of light in 4 differnt ANDERSS.) and Yomogi have different in 4 plots is certain weed height and amount and it can be said that the light under distributions intensity while weeds decreases suddenly. at a 30 cm. from the weed top. of light under weeds at 10 cm. from the ground in which relatively plot-2, growing low weeds grow, it's high weeds, average is 17.5 % ±16.3, and 21 % of plot area is more 3000 Lux. The horizontal shown than so dark, in Fig. 1-4. average 3000 Lux, In the plot-1, in another intensity is 3.5±3.9, 75 % of area is more dark than Reduction clear that carbon under the of photosynthesis photosynthesis activity of trees with light intensity with the reduction light : It is to of is proportional intensity some extent—about dioxide. A experiment various light 20 or 30 K Lux, and the less light, of the uptake of isotope Labeled labeled less assimilation dioxide carbon of labeled is done intensity. CO2 made BaCO3 (37.8 ,ac/ 37.8 mg. BaCO3) was filled in the assimilation chamber shown in Fig, 1-5, in which 3 kinds of Sugi (Cryptomeria japonica D. DON) branch were set and forced to assimilate According Interception ground like by shading. for 3 hours under 7, 4, 3 K Lux because light, at 25° C temperature. it was clear that light to the to Fig. 1-6 shown as the result of Sugi was reduced of light by planted of this experiment, the photosynthesis of light reduction. trees intercept weeds from the forest-stand trees : Also planted trees expell weed, and at last, planted diurnal under change Now, 2 examples, tion of light intensity as follows : 6year-old through side from the in its projection, ground are of light under young Sugi tree and varia are shown in Fig. 1-7, 1-8 and 1-9 as its shadow at 30-50 cm. and most of 20 % of light to same area forests, the light per intensities unit area, intensity old Sugi forest, Sugi intercepts But in older influenced out a day, and also intercepts 80 % of light to only 20 % area of north number by tree ground surfaces are intercepted 80-99 % of light by trees. Discussion : As mentioned above, in the extent of light 30 K Lux, any interception tree growth. comperatively On the are trees severely But completely It is enough 2. Nutrient high. other is unfavourable And besides, the compensation hand, growing in the season surveyed of tree. that point from 2 to with is to plant forest, on CO2 assimilation connected of young seedling They need at least 50 % of the sun's light. field, like most Japanese and Without have any intercepted weed control, there about 150 cm.----weeds, sun light planted to a lot of high during this cannot develop survey destroy or will die. indicates the weeds, concerning light, it is not necessary but to control only its height to less 1/2 length. for tree growth capture by weeds to reach 50 % of the light. It can be said the most damaging is the capture to a forest, In this experiments of nutrient, section, how especially weeds lysimeters it is often disturbed influence of weeds on trees When fertilizers or capture or seedlings are applied of soil and from the the amount added nutrient. the uptake in its uptake disturb by trees or seized by weeds. are discussed added nutrient, and how weeds suppress used pots, the tree growth and field, and also is described and shapes 1) Influence of weed and tree roots connected of nutrient speaking, capture fertilizer upon with nutrient absorption. japonica) growth. factor to tree Sugi (Cryptomeria is most Generally application important growth. It is, however, obserbed very often that when fertilizer only the growth of trees but also that of weeds are promoted even cannot if fertilizer grow is not added weeds grow vigorously, It is certain after to tree that planted there fertilizer while normally. is nutrient is applied, not in forest. And weeds by weeds. rye tree among capture Sugi growth at 4 months added (N 5.0 or 10.0, P2O5 2.5 or 5.0 K2O in concrete pot sowed Italian 2.5 or 5.0 g/m2) was grass seeds shown in Fig. 1-10, are shown in Tab. 1-2. According to this table, weeds suppressed growth in elongation of tree to less 1/3 in comparison with nonherbal tion rates pot. (Tab. Lower nutrient 1-4) indicate contents it was in tree caused leaves (Tab. 1-3) and absorp capture by weeds. while Sugi tree only Two disadvantageous by nutrient It is noticeable 4or9%. The plantings fertilizer, same that weeds uptook 30 % of added fertilizer, results were obtained in 2nd experiment. (Refer to Tab. 1-6) carried out in next year used same pots and especially remarkable reduction of nitrogen absorbed under the herbage (less 1/2 mg. N/ tree than without weeds). In 1966, using lysimeter (1.5 m. x 1.8 m. area, 0.8 m. depth, shown in Fig. 1-12) with This autoirrigation experiment, and which protecting applied phosphate) reduction rainfall, fertilizer, 15.0 and reduction the nutrient capture was studied between Sugi and Kentucky 5.0, P2O5 (Ammonium resulted caused a conspicuous loss with drain differences 1-16, 1-17.). On the other hand, it is well known that water soluble phosphate is fixed by soil easily and it is to hard to be avairable tion rate of phosphate by trees is low, and phosphate by weeds. reason a experiment Pref.. was done with Sugi trees using 32Plabelled Experimental area was divided in two, one was (294.6 pc/g P2O5) for a month at Kyusyu University The experimental herbs. without For this superphosphate Forest for plant. In forest, the absorp there is a much ability to seize between blue grass under high density of Sugi (12 trees/2.7m2). N (Urea and Ammonium K2O (Potassium of elongation chloride) phosphate) 2.5 g/tree, the in a not so remarkable as shown Fig. 1-13, but are no significant of the tree weight. was measured, Also in this experiment but there water from lysimeter the plots with and without grass (Tab. 1-11, Fig. 1-14, 1-15, in Fukuoka with herbs and another and measured At 15 days and 35 days after an applica the sample trees were uprooted of absorption of added phosphate tion of 2.5 g. as P2O5 of labelled superphosphate, for radioactiyity. The amount by trees and herbs calculated 25 mg. after herbs, woody besides Even without but from their activity for Sugi, 15 days in 60 cm. were, and and as shown no difference 7.9 mg. in Fig. was 1-18, found 9 mg. with were sample in the after and 15 days, without by and circle. and that 35 days after 2.7 mg. after 35 days the absorbed tree, same with while of plants 20 and if existed diameter were circle seized around 288 of added rate average phosphate had rate no by herbs differences absorption the significant herbs that between 12 %, 86 % area. herbs, is 1 %. which of the fact all plants amounted herbs captured applicated to of trees phosphate It is very was noticeable by added available in the 2) Root weight of weeds in young forests. Weed roots grown in the young forest located at the foot of Mt. Aso in middle Kyushu and dominated by Susuki (Miscanthus sinensis), were dug up and measured. The weights per m2. were shown in Fig. 1-19, 1-20. It was found that more than 90 % of root weight was Susuki and they were distributed to the extent of 20 cm., almost 10 cm. depth from the surface. The fact that Susuki root consist of net-like subterranean stems give a suggestion of its nutrient and water capture. 3) Roots of young Sugi trees. Sugi has deeper roots than some other conifers such as Hinoki (Chamaecyparis obtusa SIEB. et ZUCC.), and the root of old Sugi reaches to 250 cm. or so. Its root are so loose in comparison with that of herbs that Sugi is placed at a disadvantage on nutrient uptake. The results of root system study are shown as follows : 5year-old Sugi root in cultivated farm in Fig. 1-21, 1-22, 1-23, 1-24, 1year-old Sugi root treated by fertilizer in Fig. 125-4-43. 3. Water capture by weeds Whether the weeds capture nutrient or water, this capture or competition takes place in some extent. If there are sufficient nutrient or water to be consumed by tree and weeds, there would be no competition. Generally it would be true for forest soil to have enough moisture content for the survival of trees. So the reduction of tree growth caused by water capture appears only in dry condition of soil, especially that which has been dry for long time . More or less, however, the water capture occurs in any forest with herbs. By using lysimeters in which Sugi and Kentucky blue grass were growing together shown in Fig. 1-12, a experiment concerning this problem was done by means of measuring the soil moisture at 3 and 20 cm . depth. The gypsum block method (Fig. 1-44) was used for successive measurement of soil moisture. Fig. 1-45 shows the changes of soil moisture of each depth as electricresistance value of gypsum block. According to this figure, soil surface and this drying at 3 cm. depth up in herbal begin to lose its moisture 2 days after saturation, plot is more conspicuous than nonherbal one, while the moisture at 20 cm. depth never changes at least for 7 days, in spite of drying completely at nearly ground level. From this experiment have much influence in a lower of ground, depth it is considered that water capture deficiency by weeds does not to lower part be dead. and upon Sugi growth, because a lot of Sugi root is distributed reaches than 20 cm. and when water in the soil. Influences are applied trees some of Herbicides it is sure, weeds distributed in upper part will already will never seize water Chapter When only weeds same time. trees 1. 2. upon Forest Trees weeds, not upon herbicides but In this in the forest or nursery or seedlings physiological are injured influences to control also planted chapter, more or less at the of herbicides are discussed. upon transpiration are treated closure the stomatal tissue. decreasing seedlings of the treated amount of water absorption solution of of obtusa) with 5 % of water and water of trees with chemicals, caused they decrease their transpiration or death of by chemicals, or destruction Influence When the trees through conductive Hinoki sodium and In this experiment (Chamaecyparis chlorate, to leaves 0.05 % of 2,4-D-Na salt, 2 % of dalapon as control, by using of water such while When treated or roots, was observed for 8 days in September as total days after controled amount potometers shown in Fig. 2-1. The results are shown in Fig. 2-2, 2-3, 2-4, absorption as becoming a decreasing treatment severely. and the amount of water was done yellow or pale could be found absorption to leaves, could sodium at 2-5 chlorate per unit time and tree weight. be observed Visible damage treatment, after. water at 2 days absorption No suppression was found in treatment of roots, and was most in 2,4-D. In this experiment also the influence of ammonium sulfate was surveyed. Water absorption by Hinoki seedlings treated with 5 % as sodium chlorate and 0.2 % as ammonium sulfate, mixed Treatment that with sulfate solution, sulfate 0.05 % as 2,4-D and 0.2 % as ammonium solution to roots, are shown in Fig. 2-5. sulfate, treatment sodium chlorate of the to a stop of water sulfate (Fig. 2-6). absorption promoted ammonium and 0.2 % of ammonium and sodium of water chlorate 2,4-D solution treatment, mixed only brought but ammonium trees at 5 days after absorption much more than control Some found that investigators dicussed the herbicides considered as antitranspirants, by their chemical that and it is tissue 2,4-D and dalapon close stomata of trees actions. It is, however, was more effective closure tration 2. was of herbicides. in this experiment death of conductive absorption to stop water absorption, These results and reducing by stomatal not so noticeable. might be due to too high concen Influence Respiration factors upon respiration of trees change inhibiting closure of herbicides to respiration of substance of action of stomata to respiration and is influenced of respiratory and of plants. of 1 and 2 % sulfate as in so on. by enzymes, Many is a kind of chemical such as temperature, substance, many decreasing investigator In this solution mixed control, The which including amount of respiratory reported section, the actions the actions chlorate, of Hinoki seedlings of sodium solution, 1 % sodium chlorate and 0.2 % ammonium 1 and 2 % of dalapon, and discussed. of carbon seedlings 250 and 500 ppm of 2,4-D and water in the air through closed bags were investigated concentration Hinoki infrared of exhaust 1year-old dioxide were set was measured by using the device gas analizer shown in Fig. 2-7. Untreated sample tree exhausted 0.465 mg/g The results were shown in Fig. 2-8, 2-9 which were ploted as carbon dioxide by seedlings. samples except dalapon treated took out much more that of 2,4-D (250 ppm) treated one reached to 3.2 that generally after 72 hours the respira were forced per hour, while all treated carbon dioxide, especially times as untreated found reduced one. It was tion was to respire 3. in this experiment gradually, but most trees treated treatment. with herbicides intensively in first stage after Influence Many upon photosynthesis. interfere stomatal the process the carbon such with photosynthesis closure, some by various herbicides way of chemical as triazines or herbicides actions. In addition ureacompounds ATA destroys of chlorophyll actions absorbing caused water to the inhibit decrease such of photosynthesis. and this reduction Furthermore, other of inhibition dioxide assimilation. chlorophyll in leaves and causes chlorosis, as oxidation by herbicides reduction. of protoplasm, or decomposition of protein included or interferences as mentioned in plant, are all connected of carbon dioxide fixation were investigated. 1 (Fig. 1-5), and in Chapter with photosynthesis of Hinoki seedlings The method In this experiment, the reductions the same which were treated with some herbicides was almost 14Clabeled hours. chlorate Then CO2 assimilation the was carried activities out under 7000 Lux of light for 3 photosynthesis in proportion to radioactivity were compared interference In the was with each other. of CO2 fixation treatment, When 2,4-D 500 ppm, sulfate and dalapon was not so severe trees sodium chlorate 3 %, sodium to leaves, intensive which (Fig. 3 % mixed ammonium 2 % were treated (Fig. 2-10, 2-11), while effects were found when treated root fixed by untreated tree to root by means after 24 hours of culture in herbicide solution. 72 hours all treated fixed CO2 only 40 % of that and less 20 % after the fixation rather 2-12, 2-13). And in this experiment ammonium thesis sulfate because of much the effect to promote but it hindered concentration functions higher the of CO2 by mixing photosyn that of than was expected, than helped solution of mixed single solution. Some treated herbicides disturb of photosynthesis and for this effect in these experi tissues, roots or disturbed plants are driven away to death. that the reduction of tree or tissues of CO2 fixation caused such as conductive It is, however, considered root apex cells, and death ments was due to the death of some tissue, carbon dioxide assimilation. 4. Translocation When move translocating function 2,4-D some of 2,4-D in plants herbicides conductive ability called tissue, by herbicides translocating type are treated with their to plants, killing they The effect through then display their actions has large connection through epidermis to kill plants. of herbicides for weeds besides the penetration against treated confusion In this section Himemukashiyomogi is reported (Erigeron on bark and the recovering translocating (Miscanthus Yabutsubaki study of sinensis), (Cameria 2,4-D caused by chemicals. the results canadensis of prelimirary Susuki L.), and japonica), to Sugi (Cryptomeria japonica L.). Labeled 2,4-D which was 12.1 mc/mM, that is, 54.7 pc/mg of specific activity, and 300 ppm solution of Na-salt was used. As shown scarecely was little after in Tab. 2-1, when 2,4-D was treated and it was estimated absorbed, than other while hand, the amount in lateral when to terminal of residue part moved, in treated of Sugi, it part it showed a pot 84.8 % of 2,4-D more movement treatment. branch treatment in the terminal, and residue 2,4-D was 72.4 % at 27 days to soil in the On the treated planted Sugi, it was found 20.8 % of absorped 2,4-D in top, 79.2 % in root. It was also difficult to move in Yabutsubaki treated with labeled 2,4-D to terminal not move branch, and and almost all 2,4-D penetrated treated part after through 27 days leaf epidermis (Tab. 2-2). did The remained in the most radio activity originated in Susuki, 2,4-D was in translocated 2,4-D was detected plants treatment in the bark, vascular Poaceae, untreated it never system. one of most troublesome At 27 days after detected in treated belong to Family to young leaf, 72.9 % in to older leaves, at road was shown part moved. in Himemukashiyomogi, on leaves and stem. Half typical amount broadleaved of absorbed weed found in middle part treated 2,4-D was detected in Tab. 2-3. Translosating 27.1 % of absorbed part, and another as translocated 2,4-D, while, when it was treated Moving with 2,4-D side, was easier (Tab. 2-4), and only 27.5 % was remained in the lower part, especially 5. Sodium chlorate It is said that our soil. country, The water tendency uptake sodium in leaves and stem. and run-off from soil chlorate, the intensive and tend herbicide used most often in from blue of Na concentration is easily soluble in water to run off with water Sugi tree and Kentucky to run-off was surveyed as the change in drain from 0.3 m3. capacity pots planted grass, and applied sulfate together. not equal absolute of this shown it can after sodium amount. among amount fact, the 33 g. of sodium chlorate or 33 g. of it and 72 g. of ammonium Unfortunately the amounts of drain water for 27 days were the various treatments so it was impossible to discuss the as of Na run-off which was proportional changes of concentration From comes to drain water. In spite of Na each day were detectable these changes (powder) after the to an end chlorate, of Na concentration, starts end in Fig. 2-17, 2-18, 2-19, 2-20. soil surface surlfate Much more chlorate application was mixed is compeled sodium and be said that the run-off of sodium chlorate into sodium from 10 days and is of of run-off 2 months, ammonium to come chlorate a little later and mixed and to run off much use of sodium chlorate more and ran off from herbal pot than nonherbal pot, and the difference between single ammonium sulfate was not distinct. It is considered easily soluble that trees like in water sodium can absorb a large amount of herbicide if it is cultured chlorate. When Hinoki seedlings in 3 % water solution of sodium chlorate for 10 days, as shown in Tab. 2-5, a considerable amount of sodium were found in Hinoki. As 10-20 times sodium of that was in normal Hinoki was detected by flame photometer, sulfate to sodium and its absorption chlorate solution promoted by addition of ammonium (Tab. 2-5). The calculated from solution on assumption fatal dose of sodium chlorate for Hinoki seedling, which was absorption amount of Na, were 27.7 mg/g dry weight in single and 44.8 mg. in mixed solution was absorbed as equivalent sulfate amount of ammonium sulfate that Cl03 as Na+ by seedling. nearly 2 times of sodium chlorate This fact indicates that ammonium helps trees to absorb more sodium chlorate, that is, lessens the damage caused by sodium chlorate when it is used in forests. 6. Influence upon seed germination upon germinations application treatment after of Sugi seeds treated was observed is given in Tab. 2-6. with 4 herbicides The germination by in and the number of germinated The influence means seedlings 4 months of preemergence plot treated with herbicides was a little less than untreated, especially more remarkable with simazine (CAT), there are, however, no significant differences between Hinoki each plot. (Chamecyparis And the same results obtusa) were obtained (Pinus at the experiments Thunbergii for and Kuromatsu solution PARL.) (Tab. 2-7) seeds. Even soaking from herbicidal in herbicidal toxicity for 15 or 24 hours, seeds did not suffer Two examples of the weeping grass for germination. seeds are shown in Fig. 2-21, 2-22. 7. Influence In the upon growth or nursery considerably severe influences of herbicide on tree forest growth are frequently found. Most intensive damage was observed on young Sugi seedlings at 2 or 3 months after germination caused by treatment with CMU, CAT and C1-IPC (Tab. 2-8, Fig. 2-23), while Kuromatsu application When Thunbergii) and Hinoki (Tab. 2-9, 2-10, 2-11) when (SES), or 0.1 or 0.2 g/m of simazine to seed beds. the herbicidal as shown application in Tab. 2-13. little damage was found on 0.1 or 0.2 g/m2 or sesone of preemergence methods Kuromatsu results at shown (Pinus Hinoki (CAT) were used by means tests and using also the treatment transplanted the same in Tab. 2-12, no damage was found to 1year-old (Chamecyparis obtusa) as shown Fig. 2-24, 2-25. As indicated by these results, usual doses or treatments damages we should control, by many this reason, to seedlings control it can cultivated in the nursery. that objective In the forests trees. weeds for 6 or 7 years after planting application unfortunately many do not give any of our country, Without weed For out has not be expected yet out trees would grow normally. were carried or herbicide the past method during many herbicidal investigators, tests at young forests no flawless tests been found until now. The author carried application several years, which included spot spray application method and combination method of herbicide and fertilizer. If the spot spray which is a method to spray powdered or water soluble herbicide in a circle around the planted tree is used, no remarkable damage ever appears, to the the as shown in Tab. 2-16, 2-17, as results The influences and of growth. method herbicidal The is expected. for Sugi and in Tab. 2-18, are surely have due any 2-19 for Hinoki. application more upon forest trees of herbicides less use maybe dose, and the more use of herbicide, does not suppression influence, but no weed control Chapter 3. Influence of herbicide trees and shrubs The use effects of of fertilizer many and upon weeds and undesirable Chapter 4. herbicidal application and herbicide connected about and mixture In this two chapters of herbicides application After vegetation southwestern the are reported methods part investigations also discussed in forest adscendens with the practical effective and as follows : uses economical of herbicides. of Japan, They are summurized nurseries clear that investigations of flora (Digitaria and forest in Kyushu, the main weed most cultiva and it became in nurseries was Mehishiba HENRARD) in many ting beds were covered with it (Tab. 3-1, 3-2, 3-3, 3-4), while in forests, especially young forests, Susuki 3-6). These been weed expelled by the was overwhelmingly dominant forests (Tab. 3-5, vegetation under trees forced a change reduction of light and weeds would have by growth grassy of trees gradual caused (Tab. 3-7 (1), (2), (3), (4), (5), Fig. 3-1, 3-2, 3-3). Dalapon was most effective for preparing beforehand trees, and the overall spray of 60 kg/ha the dominant of dalapon princeps destroyed almost entirely weed, Susuki, plain to plant as powder over the grasses PAMPANINI), then the plain changed the Carduaceae its flora into that which Yomogi (Artemisia plant with broad leaves, was dominant (Fig. 3-4, 3-5) after 3 years. For both purposes, killing useless broadleaved trees and shrubs for prepara tion trunk of reforestation wound made and by sprout axing control or cut from surface stumps, spray of soluble treatment to phenoxy compound herbicides such as 2,4-D or 2,4,5-T were considereably carried even out in several herbicide economical that useful (Tab. 3-8, 3-9, 3-10, forest nurseries for weed control used as in Kyushu, in nursery, with were 3-11, 3-12, 3-13, 3-14, 3-15). After the investigations simazine especially fertilizer On avairable introduced the was selected more other effective hand, and as most effective when mixture (Tab. 3-16, 3-17, 3-18, 3-19, 3-20). it was found sodium forest chlorate and dalapon for weed suppression in young if the spot or belt spray was (Fig. 3-11, 3-12, 3-13 (1), (2)). Ammonium and the NAKAI) destroyed and sulfamate Koshida was to fern the recommendable Urajiro dichotoma sufficiently herbicide for fern control, glaucum dominant, were use of 6 kg/a intensively vegetation, (Diploterygium (Dicranopteris and suppressed BERNHARDI) its resprouting (Tap. 3-21, 3-22, Fig. 3-14, 3-15, 3-16) Silvicultural use. objective trees use of herbicides the foresters and for workers, means physiologically expect the and easy method effective and economical harmless, use. both for From this It is certain inexpensive, of herbicidal point of view, the author proposed in practice to introduce the preemergence and preplanting method and co-use of fertilizer in forest nursery, and spot or belt spray method Tab. 4-4). establishment herbicide. And and also co-use of herbicide for this introduction silvicultural there and fertilizer is needed, combined in forests by all with (Fig. 4-2, the of the use means, of systematic opperation