MENANAM POHON UNTUK

MEMANEN AIR HUJAN

Soemarno - psdl ppsub 2013

MENANAM POHON

UNTUK MEMANEN AIR

HUJAN

Kombinasi teras bangku dan vegetasi pohon untuk memaksimumkan hasil panen air hujan

Sumber: www.thecottagekey.com/watershed.htm

Siklus air hujan mengisyaratkan besarnya peluang untuk memanen air hujan

Karakter pohon dapat dimanfaatkan untuk memanen air hujan dan energi

matahari sebanyak-banyaknya

SIKLUS HIDROLOGI

Diunduh dari sumber: http://www.cesm.ucar.edu/models/clm/hydrologic.html ….. 31/10/2012

The hydrologic cycle over land includes interception of precipitation by plant foliage and wood, throughfall and

stemflow, transpiration, soil evaporation, canopy evaporation, infiltration, runoff, soil water, aquifer recharge, and snow.

These are directly linked to the biogeophysics and also affect temperature, precipitation, and runoff.

EVAPOTRANSPIRASIThe total evapotranspiration (ET) can be broken down into the Tr is transpiration, Ei interception evaporation, and Es evaporation from the bare soil and forest floor litter. On an annual basis in a forested environment, transpiration is the dominant component of ET, followed by interception evaporation and then bare-soil

evaporation. However, during precipitation events, interception evaporation becomes the dominant component of ET during

rainfall and during the hours immediately following precipitation.

Diunduh dari sumber: http://www.grin.com/en/doc/268148/observations-of-the-transient-characteristics-of-the-hydrological-balance…..31/10/2012

INTERSEPSI

Diunduh dari sumber: http://www.answers.com/topic/interception….. 3110/2012

Interception refers to precipitation that does not reach the soil, but is instead intercepted by the leaves and branches of plants

and the forest floor. It occurs in the canopy (i.e. canopy interception), and in the forest floor or litter layer (i.e. forest floor interception. Because of evaporation, interception of liquid water

generally leads to loss of that precipitation for the drainage basin, except for cases such as fog interception.

Akar Pohon

Diunduh dari sumber: http://www.oakwilt.com/articles13001/anatomy2.html ….. 31/10/2012

Tree species are not necessarily "deep-rooted" or "shallow-rooted" -- certain species are more or less sensitive to various

levels of moisture, oxygen, and minerals. Often roots will "bounce"  off a soil hardpan or a high  water table, forming

surface roots where other species may not be able to live at all. 

• Provide social, ecological, and economic benefits• Their leaves and roots clean the air we breathe

and the water we drink

Trees: The Original Multi-taskers

Their beauty inspires writers and other

artists.

• Save Energy; Improve air quality• Extend life of paved surfaces• Increase traffic safety• Increase real estate values• Increase sociological benefits• Protect our water resources

Benefits of Trees in Urban Areas

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All water is part of this cycle

Storm Water dan Siklus Hidrologi

• Urbanization dramatically alters the hydrologic cycle– Increases runoff– Increases flooding frequency– Decreases infiltration and groundwater recharge

• Nationwide impervious surfaces have increased by 20% in the past 20 years

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More Trees Means Less RunoffSome Statistics

• Fayetteville, Arkansas: increasing tree canopy from 27-40% reduced their storm water runoff by 31%

• South Miami residential study found that a 21% existing tree canopy reduces the storm water runoff by 15%

For every 5% of tree cover added to a community, storm water is reduced by approximately 2%

Bagaimana pohon mengendalikan “Stormwater”?

• Above ground effects:– Interception, evaporation and absorption of precipitation

• Ground surface effects: Temporary storage• Below ground effects: Infiltration, permeation and filtration

Infiltrasi dan perkolasi air-hujan dalam tanah merupakan dua proses hidrologis yang sangat diperbaiki oleh adanya

vegetasi pohon

EFEK POHON TERHADAP LINGKUNGAN DI ATAS TANAH

• Intercept rainwater on leaves, branches and trunks – slowing its movement

• Evaporation of some of this intercepted precipitation of the tree surfaces

Absorption of a small portion into leaves or stems

Leaf litter and other organic matter can hold precipitation and stemflow on a site, reducing the

amount and peak rates of runoff

Efek Pohon terhadap Lingkungan Bawah Tanah

Roots and trunk bases of mature trees tend to create hollows and hummocks on

the ground

• Organic material from leaf litter and other tree detritus tends to increase infiltration rates by increasing pore spaces in soil

• Organic material also increases the moisture-holding capacity of these sites

• Root mats of trees also tend to break up most soils further improving infiltration and moisture-holding capacity

Efek Pohon terhadap Lingkungan Bawah Tanah

EFEK LINGKUNGAN-BAWAH-TANAH

• Deep roots tend to improve the rates of percolation of water from upper soil horizons into lower substrates

• Trees take up water through their roots that is eventually transpired onto leaf surfaces and evaporated

• Tree roots act as natural pollution filters (biofilters) using nitrogen, phosphorus and potassium

TAJUK POHON - KENYAMANAN

• Set to protect a community’s green infrastructure and maximize the environmental benefits

• For metropolitan areas east of the Mississippi– Average tree cover for all land use 40%– Suburban residential 50%– Urban residential 25%– Central business districts 15%

MULTIPURPOSES …?

Ruang terbuka hijau – Taman pohon buah-buahan

COMPLICATING FACTORS

• Presence of soil compaction• Presence of soil textural discontinuity

– Has the site been disturbed in the past?• Management of the ground surface

– Is litter layer removed?– Is soil surface exposed in winter?– How much of the surface is like a natural forest?

(number and size of trees)

PERGERAKAN LENGAS TANAH

• Forces affecting the energy of soil water– Matric force (absorption and capillary)– Gravity– Osmotic forces

• Field Capacity is the amount of water held in the soil after gravitational water had drained away

• Movement of water is the soil is controlled :– Gravitational forces if saturated– Matric forces if unsaturated

Tanah mempengaruhi Infiltrasi air hujan

• Infiltration is the mode of entry of all water into the soil • Rate of infiltration determined:

– Initial water content– Surface permeability– Internal characteristics of the soil

• Intensity and duration of rainfall• Temperature of soil and water

Tanah mempengaruhi Infiltrasi

• Microrelief under trees provides catchment basins during heavy rains

• Removal of litter layer reduces the infiltration rate• Forest soils have a high percentage of macropores• The frost type found in forest soils promotes

infiltration year-long

Soil compaction reduces the infiltration rate

PENTINGNYA SERESAH DI PERMUKAAN TANAH

1. Absorbs several times its own weight2. Breaks the impact of raindrops3. Prevents agitation of the mineral soil4. Discourages formation of surface crusts5. Increases soil biotic activity6. Increases incorporation of organics7. Slows down lateral movement of water

POROSITAS TANAH

• Develop in old root channels or from burrows and tunnels made by insects, worms or other animals

• Lead to better soil structure• Increases organic matter incorporation• Increases percolation rates and root penetration

TANAH DI BAWAH TEGAKAN HUTAN

• Granular– Found in woodland soils with litter– May be more permeable

• Honeycomb– Has loose porous structure– Found in highly aggregated soils and also

formed in organic layers and litter layers

AIR-TANAH-TANAMANThe proportion of the soil occupied by water and air is referred to as the pore volume. The pore volume is generally constant for a

given soil layer but may be altered by tillage and compaction. The ratio of air to water stored in the pores changes as water is

added to or lost from the soil. Water is added by rainfall or irrigation. Water is lost through surface runoff, evaporation (direct loss from the soil to the atmosphere), transpiration

(losses from plant tissue), and either percolation (seepage into lower layers) or drainage.