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Illustro

Harvestability of large Catha edulis trees

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So, my friend Pablo's red khat sapling is just nearing the 2m mark, and should top 3m by the end of summer judging by growth rates - Pablo needs to make decisions on what to do with the plant.

Pablo and his closest friends are total amphetafiends, so he thinks he will likely harvest and share the gift from the earth quite regularly during the summer months. Pablo though, doesn't want to maim the tree by stumping it, he would much prefer to let it grow into a big happy tree, plus he quite fancies the idea of being able to climb up it, chew some leaves, and get pranged in the canopy just like a koala.

So, Pablo wishes to know from the khat veterans out there; if he lets his plant grow big and happy, will there be enough easily harvested (and potent) fresh tips to sustain a ~1kg harvest every week or so over summer?

Pablo lives in a very productive area, with even yearly rainfall, at amounts optimum for khat (~1200mm pa), very fertile soils, and a subtropical climate - so the plant should have no problem supporting it, just the quality of the product is in question.

Gracias!

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I doubt it. 1kg is a lot of leaf, I don't think many shrubs out there would generate that kind of biomass. If Pablo had 10 plants then he might get away with 100g each per week if they were big.

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It's not the height of your plant that will dictate how much you can harvest, it's the growth rate

This is determined by a number of factors, your climate, the characteristics of the season, any nutes you put into it, and any stressors such as pathogens, frosts etc

It's a bit unrealistic to expect predictability until you've been harvesting it a few years running

I had a huge 4-5m narrow leaf Catha for a few years, doubt if I could have gotten a kilo a week over the growing period- that's 20 odd kg a season, and I harvested hell out of it for events etc until I found out that was illegal.

Last few years a stem borer got into it and radically reduced it's growth.

Last year I cut most of the big affected stems down and figured well, that was it, it would never recover. It's 20+ years old. This spring I'm seeing 30cm shoots up to 1.5m away from the original base. Nice thick healthy green shoots they are too, I reckon this is the plant's way of defying the stem borers, by starving them out for a few years til it re-establishes

Coppicing *could* be one way to go with a narrow leaf. But I wouldn't try it on a precious individual unless I had another to back it up

Moral: Plants aren't machines, try not to demand so much for them and they'll give you much more

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Cheers for the replies, though I seem to have jumbled what Pablo was trying to ask, I'm not very fluent with español; he wanted to know if there was much difference in fresh shoot yield and quality between a large free-growing tree, and a coppiced plant?

Pablo lives where this is legal, so no problems with the legalities. He appreciates that 1kg was probably too much to ask, though he says he does imagine he will be a heavy consumer.

Muchas gracias, amigos!

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the only problem with trees these days is they are easily spotted, in a suburban area your best off keeping them under fence height. i heard or read somewhere that 7yo khat is the real beginning of nice tea, under that and something isnt quite there, im not sure tho just speculation.

it doesnt matter where they are spotted on what type of property, once they are found publically certain people wont stop until its all gone and they will invade properties, jump fences, kill dogs you name it...very tragic. i think khat responds well to some hard core pruning and once it is 5 years old i reckon you just bite the bullet and cut the main trunk right down to 30-60cm and the thing will have 2 new solid trunks or more within a year, then they shoot out all the lovely shoots from the base which given time will bush it right out or you can pull them and have surefire easy rooted cuttings if you pluck them out, either way its a win win if you plant them out too, preferably heaps of them along a fenceline for example to make a funky 40 metre hedge.

just cant really see the point in a tree, seriously a well maintained and trained single hedger would be just as productive as a single tree, it hard to do but chop that sucker in half.

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an ethiopian (they use red variety there) told me with a fair bit of conviction that it's wrong how people hack them down. he was talking about using a pair of scissors, and going around the bush like that, and he wasn't talking about small plants either, so he seemed to be totally against hard pruning much less coppicing.

i can't say whether his opinion is valid, just passing on what i was told.

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Pablo doesn't need to worry about it being spotted, he lives rurally; the tree could only be spotted by people right in on his property. And, Pablo really doesn't take too kindly to trespassers, that's for sure; he is well versed in clandestine tactics, he learned from the best.

7 years you say? It would be interesting to do an alkaloid cohort study, see how these rumours measure up, I've heard so many different ideas on the topic.

The hedge idea is brilliant! Plus, one could inter-plant the hedge with red tipped Photinia sp., and if kept well pruned, prospective thieves would be none the wiser to the hidden death-trap! Nothing quite like a quid of hydrogen cyanide to start the day, a deviant idea indeed..

:devil:

EDIT: @Thunderideal:

Hmm, interesting, that's a good point, just prune back the small branches a bit, it would have to induce the growth of fresh tips.

I was thinking of something similarish (to do with alkaloid boosting though), but it was a rather fancy full idea. I was wondering whether the alkaloids in khat are constitutive (always the same), or inductive (responding to attack). I read a few studies some time ago, testing the mechanism of how inductive responses are actually induced, whether it was just due to foliage removal, or whether it was triggered by another factor. One thing that came up in many inductive plant species, was that alkaloid production was unaffected by foliage removal (via pruning equipment), but showed strong responses to herbivore saliva, specifically some proteins in it; there was more of an alkaloid response to the application alone of these proteins to the foliage, than there was from foliage removal. So, I was thinking, Pablo could try let goats, cattle, horses, or some other herbivore which could have the salival proteins needed to trigger a response, graze the plant.

Though, if Catha edulis is inductive, I'm not sure if it would be possible to find domesticated farm animals with the right salival proteins to trigger a response, with most being non-native to its range; but it could be interesting none-the-less.

Edited by Illustro
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Pablo doesn't need to worry about it being spotted, he lives rurally; the tree could only be spotted by people right in on his property. And, Pablo really doesn't take too kindly to trespassers, that's for sure; he is well versed in clandestine tactics, he learned from the best.

better stay away from copperhead rooaaaad

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an ethiopian (they use red variety there) told me with a fair bit of conviction that it's wrong how people hack them down. he was talking about using a pair of scissors, and going around the bush like that, and he wasn't talking about small plants either

interesting, maybe cos they farm them there is no need to speed the process up as there is a constant supply. if you only have one plant to work with then you gotta speed the process up a bit.

i couldnt see his logic though, when pruned they go mental with fresh shoots when a tree of the single trunk style i dont recall seeing as much fresh tip growth. also if you can get rid of the ladder its safer and easier.

I was thinking of something similarish (to do with alkaloid boosting though), but it was a rather fancy full idea. I was wondering whether the alkaloids in khat are constitutive (always the same), or inductive (responding to attack).

temperature man, sometimes they also emit a tell tale scent which must be an indicator i believe. have tried to narrow it down. first got the idea from some online text which said farm harvesting was always done at a particular time, i think it was 11am just before the midday heat and on the warmer days. honestly i find khat totally fickle in nature, by that i mean one day its strong the next it is weak the next it is strong.

the cold days are not worth picking as it is weak, the 35c + days are also weak....heaps of other unfounded trivia but to cut a long story short i totally believe that 20centigrade to 25centigrade on a clear sunny day with low humidity and between 11am to 1pm is the best window for best goat feed.

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Well, you would imagine that a large tree would have far superior biomass producing capabilities to a stumped or coppiced plant, seeing as the surface area available to absorb CO2 and photosynthesize would be that much greater, as well as absorb soil nutrients, seeing as root mass is directly proportional to canopy size. Just the quality of the shoots would be questionable, seeing as growth would be spread out amongst so many different meristems - definitely worth investigating..

Now, that's really interesting on the temperature effect, it seems bizarre that the alkaloids would change so much with temperate, but I guess cathinone isn't stable like most, so the need to be constantly synthesizing more would make sense. But, are you sure that the temperatures didn't introduce harvesting bias though? Like on colder days you hastily picked the closest tips to you, on hot you picked those under the shade, and on moderate days you were free to pick more selectively?

Either way, khat sounds like a really interesting plant to do some studies on, it is quite the oddity.

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yeah, coppicing may produce the most shoots, but it is an overall knock to the plant.

he did keep going on about a specimen at the botanical gardens and believed it died after being cut down by somebody else. maybe they have figured out that occasionally it is fatal. the scissor method seems like a lot more effort than the chainsaw method.

as well as feeding their goats lots of khat, ethiopians also feed their goats loads of coffee, from when they wake up right up to bedtime. that's the ticket he reckons, coffee and khat

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They harvest Psychotria leaf at a specific time too.

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I was thinking of something similarish (to do with alkaloid boosting though), but it was a rather fancy full idea. I was wondering whether the alkaloids in khat are constitutive (always the same), or inductive (responding to attack). I read a few studies some time ago, testing the mechanism of how inductive responses are actually induced, whether it was just due to foliage removal, or whether it was triggered by another factor. One thing that came up in many inductive plant species, was that alkaloid production was unaffected by foliage removal (via pruning equipment), but showed strong responses to herbivore saliva, specifically some proteins in it; there was more of an alkaloid response to the application alone of these proteins to the foliage, than there was from foliage removal.

That is very very very cool info- do you have any papers on this? It has interesting ramifications for tissue culture as well. Thanks for posting it

I was given to understand that the rule of thumb for harvesting alkaloid-rich leaf material was first thing in the morning once the dew has dried. Once the sun starts to heat the leaves alkaloids degrade. Catha has been predictable in that reguard and yes, cold or wet weather clipping does seem to yield lower concentrations. I could be wrong

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what is herbivore saliva anyway. that could mean vegans, sheep, nectar feeders or beetles. if it means vegans then go vegan and chew the leaves while they're still on the plant :P

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this data seems to back up the 5-8year maturity levels in regards to alkaloid production, the early mornings and late arvo''s for picking and that it should be stumped as a tree becomes kinda old and useless and needs to be revamped with new growth. good reading.

Harvesting

From planting a stand of khat to regular harvesting normally takes 2 to 3 years though Amare & Krikorian (1965) state five to eight years. In the first year, farmers prune/harvest a small amount mainly to train and control the growth habit, to initiate more shoots with better twigs and to reduce wind damage. This harvest, locally known as Kolasa, is mostly used for self-consumption rather than for sale. From the second to third year, however, the harvest volume steadily increases over all 8-10 years period, but afterwards the plant becomes old and needs to be renewed by stumping at soil level or at the middle of the stem.

Khat is harvested by breaking off the young branches from the main branches and trimming it to about 40-cm. Depending on growth stage of the harvestable products there are different types of khat products. Young and soft shoots are detached with the bare hands, while hardy shoots are cut off by hand tools. Each harvestable product is locally given name (s).

Khat can be harvested year round at any time of the day, but is often harvested in early morning or late afternoon. Generally, harvesting is possible 2-3 times a year from a well-established rain-fed matured khat stand depending on the age, management practice and the fertility of the soil.

If a matured plant is harvested in August, as is mostly the case, the second harvest will be followed in November. However, with sufficient rains in March well-managed and established stands can give an early harvest in May. If such is the case, harvesting is followed by a grace period from June to August for the plant to maintain itself for the second and third harvesting in September and November. Often, even in one field there are khat plants planted at different times and hence harvest is available year round

source-http://anthrome.wordpress.com/2009/06/22/celastraceae-catha-edulis-khat-mirra/

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rain-fed?

thanks for the info. it suggests coppicing after about ten years to renew the plant. i had the impression people were coppicing more regularly than that, is that not the case?

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as well as feeding their goats lots of khat, ethiopians also feed their goats loads of coffee, from when they wake up right up to bedtime. that's the ticket he reckons, coffee and khat

Dang, them goats get hooked up; they must be real tweakers, all itchy and wild-eyed fuckers I bet.

That is very very very cool info- do you have any papers on this? It has interesting ramifications for tissue culture as well. Thanks for posting it

I had a look, but nah, sorry; I couldn't find much on google scholar, so perhaps it was a book I was reading.

what is herbivore saliva anyway. that could mean vegans, sheep, nectar feeders or beetles. if it means vegans then go vegan and chew the leaves while they're still on the plant :P

I'll have to start a vegetarian cult, like the moonies or something, and get all my protein-deprived followers to lick my leaves as part of their daily ritual.

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i have reason to believe that, the first flush after a drought breaks, is stronger.

it would make sence that, the very little new and exposed shoots, get more protected by the plant, than later in the season when the whole plant is green, and feeding animals would not pose such a high danger to the plant.

the best material (young tips) can only be produced by skillfull prunning/harveresting.

in short, very good tree managment is needed to produce, the good stuff.

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Some great info PH, cheers!

Apparently, Pablo has decided he will leave his original plant to prosper and grow strong; clones shall be a plenty in no time...then the fun shall begin.

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It's my understanding the traditional process is quite a thing of patience, but I guess it may vary depending on culture anyway.

What I remember reading was that farmers grow the trees for five years with pruning and irrigation (sometimes inbetween rows of Coffea). Once they reach that age they can be harvested four times a year and the harvesting process replaces the pruning.

I would ask though, what's wrong with the "not young" leaves? Sure Pablo, leave the big leathery ones on there but don't turn up your nose at good leaves!

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the problem with leathery leaves is that, they taste like crap, compared to young shoots, and on top, are probably 10 times weaker by weight than young flush!

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There is a youtube vid that shows a guy striping the bark (the red outer skin) of the new shoots and chewing that.

If it were legal I would chew it this way as it seems to be a lot more palatable (sweeter) than the leaves and with good effects.

Chewing this way also means you dont have to have so much vegetation in you mouth when you have a chew.

I will try and take some pics on the week end of the tree I cut down last year and hit with roundup that has sprung back to life again.

It has been cut down to ground level at least 3 times

Cheers

Got

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Kenyan khat: the social life of a stimulant[@ Google Books]

The first chapter of this book contains a lot of really detailed and useful information regarding Kenyan cultivation of Catha edulis where new shoots from old trees (40+ year) are considered choice. Google Books has a copy of the entire first chapter at least when I look at it. I find the biographies of the farmers he interviews particularly fascinating; people from all walks of life united by cultivation of this plant and the financial rewards it brings compared to other occupations/crops.

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Also, this pdf refers to coppicing by Ethiopian farmers.

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I managed to take a couple of pics of the old girl today

She had a hair cut about 2 weeks ago :)

post-4489-0-47320700-1318769624_thumb.jp

The following pics are same plant

The First was taken July 2008 the second June 2009 the third September 2010 and the fourth October 2010 and the last one was taken today

post-4489-0-39171800-1318770476_thumb.jppost-4489-0-96773500-1318770533_thumb.jppost-4489-0-62931200-1318770966_thumb.jppost-4489-0-03908500-1318772267_thumb.jppost-4489-0-19497200-1318769595_thumb.jp

Cheers

Got

Edited by GoOnThen

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