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Technology for Roof Greening Using the “Eco-Sedum Unit”
I) They can grow in a small amount of soil with only a little water and fertilizer. 2) The colors of some varieties change with the season, contributing to the beauty of the landscape. 3) They are suitable for planting on a roof, because they like drying and sunshine. 4) They adapt to a wide range of pH. 5) They tolerate pests.
for the control sample, the proportion of green coverage increased remarkably from weeks 6 to 8. Figure 3 shows the value of SPAD of each unit. The values of the standard-, 1'2-, and ~-strength solutions were high, while the value for water was extremely low, probably because of a lack of nutrients. ro
- . ..- . starda rti
- ..... -1/2 .... ···1/4 -· • . -1/8
2.2 Eco-Sedum Unit
_water
The Eco-Sedum Unit is 30 cm square, 4.5 cm high, and 3 mm thick, with 64 holes for drainage (Fig. 1); it is made from polypropylene resin. The unit contains a planting mat consisting of knitted resinous polypropylene strings, 0.3 mm in diameter. The units are very portable and one can easily cover a roof with these units and remove them at will.
o
...
.
...
~----~----~------~-----
2
4
6
8
week Fig. 2. Change in the proportion of greencoverage SO 40
Cl 30
« ~ Cl.)
20 10 0
Fig. 1. An Eco-Sedum unit
starxlard
112
1/4
1/8
water
strength of nutrition
2.3 Green coverage
Fig. 3. Difference in chlorophyll density
Thirty sedwns, each about 5 cm high, were planted at 5-cm intervals in each of five units filled with venniculite. Culture solution was supplied to the units at standard, 1'2, ~, or Ye strength~ one unit was supplied only with water as a control. The sedums were maintained in a greenhouse at -25°C for two mouths, and each unit was photographed from above every two weeks. These images were subsequently processed on a computer using Photoshop software, and the proportion of green coverage was calculated. After two months, the chlorophyll density of each unit was also determined with a chlorophyll meter (SPADS02: MINOLTA). SPAD correlates closely with chlorophyll density.
J. SIMULATING THE ECO-SEDUM UNIT Figure 4 (left) shows a sedum unit after 8 weeks. Note that the coverage on part of the unit is thick, while it is thin elsewhere. If this distribution could be optimized, 1()()01o coverage would be realized more quickly. The object of the simulation was therefore to optimize the number, direction, and arrangement of sedums, in order to make the green-<:overage reach 100% as quickly as possible. We observed the growth of sedwns carefully, and employed the results in a model using the cellular automaton technique.
3.1. The rules ofsimulation 2.4 Results and Discussion
The rules of the simulation were very simple. The cells consist of growth points, nodes, and stems. A growth point cell makes stem. cells, which become node cells. After several steps, a node cell can become a growth point cell, continuing the process.
Figure 2 shows the change of the proportion of green coverage with each concentration of solution. The proportion was highest with the Yz-strength solution. The standard strength didn't produce a better result, likely because the excess nutrients had a negative effect on the sedums. The sedum given only water grew very little and was a yellow color. Except
98
3.2. Performance of simulation
lOO
;?
0
'6 'Q
Figure 4 shows an actual unit beside a picture of the simulation. These two pictures show that the simulation reflects the actual distribution well.
eu
r
8 3.3. Results of simulation
~Random
80
--- One direction --- ControUed
60 40 20 0 0
5
10
15
20
NumberofSlep
Fig. 8. Change in the simulated coverage proportion
4. CONCLUSION The Yl-strength solution produced the greatest proportion of green coverage. The simulation that we developed perfonned well in representing the actual growth of sedum. The orientation of sedums is important for increasing the coverage proportion. Factors like temperature, humidity, and light intensity will be added to the simulation in the future. Competition for nutrition and light when sedurns are very close or overlap can also be considered.
Fig. 4. Actual picture and simulation . Figure 5a, b, and c shows planted sedums oriented in random directions, one direction, and properly controlled directions, respectively. Figure 8 shows the proportion of green coverage and the munber of steps. With either unifonn or random orientations, the proportion was 650/0, whereas with controlled orientation, the proportion was over 85%.
5. REFERENCES Gaylord 1. R. and Nishidate K. (1997). Modeling nature: cellular automata simulations with mathematics. Springer- V~rlag, New York, Inc. Iijima K. (1995). Response of sedums under water stress (in Japanese). Landscape Study: 69-72 Iijima K. and Kondo M. The possibility of roof greeoing with sedums (in Japanese). (1996). Book of Greenery: 1329-1333
Fig. 5a Random orientation
Fig. 5b. Unifonn orientation
Fig. Sc. Controlled orientation
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for the control sample, the proportion of green coverage increased remarkably from weeks 6 to 8. Figure 3 shows the value of SPAD of each unit. The values of the standard-, 1'2-, and ~-strength solutions were high, while the value for water was extremely low, probably because of a lack of nutrients. ro
- . ..- . starda rti
- ..... -1/2 .... ···1/4 -· • . -1/8
2.2 Eco-Sedum Unit
_water
The Eco-Sedum Unit is 30 cm square, 4.5 cm high, and 3 mm thick, with 64 holes for drainage (Fig. 1); it is made from polypropylene resin. The unit contains a planting mat consisting of knitted resinous polypropylene strings, 0.3 mm in diameter. The units are very portable and one can easily cover a roof with these units and remove them at will.
o
...
.
...
~----~----~------~-----
2
4
6
8
week Fig. 2. Change in the proportion of greencoverage SO 40
Cl 30
« ~ Cl.)
20 10 0
Fig. 1. An Eco-Sedum unit
starxlard
112
1/4
1/8
water
strength of nutrition
2.3 Green coverage
Fig. 3. Difference in chlorophyll density
Thirty sedwns, each about 5 cm high, were planted at 5-cm intervals in each of five units filled with venniculite. Culture solution was supplied to the units at standard, 1'2, ~, or Ye strength~ one unit was supplied only with water as a control. The sedums were maintained in a greenhouse at -25°C for two mouths, and each unit was photographed from above every two weeks. These images were subsequently processed on a computer using Photoshop software, and the proportion of green coverage was calculated. After two months, the chlorophyll density of each unit was also determined with a chlorophyll meter (SPADS02: MINOLTA). SPAD correlates closely with chlorophyll density.
J. SIMULATING THE ECO-SEDUM UNIT Figure 4 (left) shows a sedum unit after 8 weeks. Note that the coverage on part of the unit is thick, while it is thin elsewhere. If this distribution could be optimized, 1()()01o coverage would be realized more quickly. The object of the simulation was therefore to optimize the number, direction, and arrangement of sedums, in order to make the green-<:overage reach 100% as quickly as possible. We observed the growth of sedwns carefully, and employed the results in a model using the cellular automaton technique.
3.1. The rules ofsimulation 2.4 Results and Discussion
The rules of the simulation were very simple. The cells consist of growth points, nodes, and stems. A growth point cell makes stem. cells, which become node cells. After several steps, a node cell can become a growth point cell, continuing the process.
Figure 2 shows the change of the proportion of green coverage with each concentration of solution. The proportion was highest with the Yz-strength solution. The standard strength didn't produce a better result, likely because the excess nutrients had a negative effect on the sedums. The sedum given only water grew very little and was a yellow color. Except
98
3.2. Performance of simulation
lOO
;?
0
'6 'Q
Figure 4 shows an actual unit beside a picture of the simulation. These two pictures show that the simulation reflects the actual distribution well.
eu
r
8 3.3. Results of simulation
~Random
80
--- One direction --- ControUed
60 40 20 0 0
5
10
15
20
NumberofSlep
Fig. 8. Change in the simulated coverage proportion
4. CONCLUSION The Yl-strength solution produced the greatest proportion of green coverage. The simulation that we developed perfonned well in representing the actual growth of sedum. The orientation of sedums is important for increasing the coverage proportion. Factors like temperature, humidity, and light intensity will be added to the simulation in the future. Competition for nutrition and light when sedurns are very close or overlap can also be considered.
Fig. 4. Actual picture and simulation . Figure 5a, b, and c shows planted sedums oriented in random directions, one direction, and properly controlled directions, respectively. Figure 8 shows the proportion of green coverage and the munber of steps. With either unifonn or random orientations, the proportion was 650/0, whereas with controlled orientation, the proportion was over 85%.
5. REFERENCES Gaylord 1. R. and Nishidate K. (1997). Modeling nature: cellular automata simulations with mathematics. Springer- V~rlag, New York, Inc. Iijima K. (1995). Response of sedums under water stress (in Japanese). Landscape Study: 69-72 Iijima K. and Kondo M. The possibility of roof greeoing with sedums (in Japanese). (1996). Book of Greenery: 1329-1333
Fig. 5a Random orientation
Fig. 5b. Unifonn orientation
Fig. Sc. Controlled orientation
99