plant transperation and water procurement
for anybody who has every worked with solar stills and knows what a waste of time they can be, i wanted to broach the subject of transpiration bags. i've searched the site and didn't find them mentioned before.
many if not most plants give off an appreciable amount of water from their leaf/needle surfaces in a proccess known as transpiration. for those of you who are inclined to carry plastic bags such as garbage bags into the wilds, this presents a reason to make at least a few of them transperent. by placing the bag over the leafy portion of a branch, stem, etc. make sure that a corner of the bag is lower than the opening and tie the opening off. this is best preformed in the morning and left to sit in what sun is available throughout the day. it also helps to place a small weight in the corner.
towards the end of the day, when things begin to cool off and the sun has lost most of its attitude, check on these bags. a greenhouse effect will occurr due to the change in light spectra as they rays pass into the bag and the temperature will be higher within. this will promote the plant tissue to release more water into the air and the cooler bag surface will allow it to condense and run into the bottom.
your selection of plants can greatly effect the amount of water given out. plants with broad leaves and soft, tender cuticles will as a general rule, be more inclined to give off thier water. unfortunately, plants with little photosynthetic surface, thick, rigid cuticles tend to transpire less, such as most of those which grow in arid environments where water is at more of a premium. the benefits over a solar still are several:
1. there is no need to denude an area of vegetation by collecting it in large amounts. a solar still can only give you a portion of the water that is in the plant material to begin with.
2. you are not limited to the amount of water contained within the portion of the plant bound inside the bag, it will be supplied by the plant all the way down the vascular structure to the roots, where the water comes from.
3. this can be preformed in the same area [on the same plant for that matter] repeatedly.
4. if done with trees, it is preformed higher than the ground level and as such, will recieve a greater amount of sun throughout the collection cycle.
if any of you also have experience with this proceedure, i would welcome any other information.
if anybody has any questions about the technique, i would be happy to help if i can.
