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8. Spacing of plantings

By observing trees and shrubs growing under natural conditions, it is often found that plants grow widely apart in low rainfall areas. Therefore, wide spacing of plantings in arid zones generally should be practiced to avoid competition for soil moisture.

The amount of water available to a tree or shrub in a plantation is proportional to the stand density. On dry sites, it is necessary to plant widely apart and to remove all competing ground vegetation; this increases infiltration of rainwater and decreases water losses through transpiration by plants and evaporation from the soil. When irrigation or mechanical cultivation is practiced, it is necessary to adjust spacing to the width of the machinery used and to ensure that plants are placed in straight rows. Actual spacing varies with species, site, and the purpose of the forest plantation. In fuelwood plantations, for example, one might prefer closer spacings than employed in other kinds of plantations. Seldom can a spacing of less than 3 x 3 meters be applied, however.

The number of trees per hectare, according to the spacing between the lines in a plantation and the spacing of plants within a line, is given in Table 4.1. For example, with a spacing between lines of 3 meters and a spacing of plants within a line of 3 meters, a planting density of 1,111 trees per hectare will be required.

Figure 4.9 Illustration showing the most common type of root doiling (one lateral root and the main root)

Figure 4.10 Ten old Pinus pinea planted with the plastic container.

Table 4.1. Number of trees per hectare according to spacing

	Spacing of plants in the lines
Spacing between lines	0.50 m	0.60	0.70	0.80	0.90	1.00	1.20	1.40	1.50	1.60	1.80	2.00	2.50	3.00	3.50	4.00	4.50	5.00	5.50	6.00	6.50	7.00	8.00	9.00	10.00
0.50 m	40,000	33,333	28,569	25,000	22,222	20,000	16,666	14,285	13,333	12,500	11,111	10,000
0.60	33,333	27,777	23,809	20,833	18,518	16,666	13,888	11,904	11,111	10,416	9,253	8,333
0.70	28,569	23,809	20,408	17,857	15,873	14,285	11,904	10,204	3,523	8,926	7,936	7,142
0.80	25,000	20,833	17,857	15,625	13,888	12,500	10,416	8,928	8,333	7,812	6,944	6,250
0.90	22,222	18,518	15,873	13,888	12,345	11,111	9,259	7,936	7,407	6,844	6,172	5,555
1.00	20,000	16,666	14,285	12,500	11,111	10,000	8,333	7,142	6,666	6,250	5,555	5,000	4,000	3,333
1.20	16,666	13,888	11,904	10,416	9,259	8,333	6,944	5,952	5,555	5,208	4,630	4,166	3,333	2,778
1.40	14,285	11,904	10,204	8,928	7,936	7,142	5,952	5,102	4,762	4,464	3,968	3,571	2,857	2,381
1.50	13,333	11,111	9,523	8,333	7,407	6,666	5,555	4,762	4,444	4,167	3,704	3,333	2,667	2,222
1.60	12,500	10,416	8,928	7,812	6,944	6,250	5,208	4,464	4,167	3,906	3,472	3,125	2,500	2,083
1.80	11,111	9,259	7,936	6,944	6,172	5,555	4,630	3,968	3,704	3,472	3,086	2,778	2,222	1,852
2.00	10,000	8,333	7,142	6,250	5,555	5,000	4,166	3,571	3,333	3,125	2,778	2,500	2,000	1,666	1,428	1,250	1,111	1,000	909	833
2.50	-	-	-	-	-	4,000	3,333	2,857	2,667	2,500	2,222	2,000	1,600	1,300	1,142	1,000	888	800	727	666
3.00	-	-	-	-	-	3,333	2,778	2,381	2,222	2,083	1,852	1,666	1,300	1,111	952	833	747	666	606	555
3.50	-	-	-	-	-	-	-	-	-	-	-	1,428	1,142	952	816	714	635	571	548	476
4.00	-	-	-	-	-	-	-	-	-	-	-	1,250	1,000	833	714	625	555	500	454	416	384	357	312	277	250
4.50	-	-	-	-	-	-	-	-	-	-	-	1,111	888	747	635	555	493	444	404	370	341	317	277	247	222
5.00	-	-	-	-	-	-	-	-	-	-	-	1,000	800	666	571	500	444	400	363	333	307	285	250	222	200
5.50	-	-	-	-	-	-	-	-	-	-	-	909	727	606	548	454	404	363	330	303	279	259	227	202	181
6.00	-	-		-	-	-	-	-	-	-	-	833	666	555	476	416	370	333	303	277	256	238	208	185	166
6.50	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	384	341	307	279	256	236	219	192	170	154
7.00	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	357	317	285	259	238	219	204	178	158	142
8.00	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	312	277	250	227	208	192	178	156	138	125
9. 00	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	277	247	222	202	185	170	158	138	123	111
10. 00	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	250	222	200	181	166	154	142	125	111	100

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