Killing Unwanted Trees With Tordon 101 Mixture

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Killin g Unw ante d
Tree s With OCTOBE R 1975 Tord on 101 Mixt ure Wayne A. Geyer, Research Forester larry E. Biles, Area Forester Nearly half the 1.6 million acres of woodla nd in Kansas needs to be upgrad ed by removin g low quality trees. An addition al 200,000 acres wooded pasture should have undesir able f, selectiv ely killed. High quality trees thus grow more rapidly to salable size.
To rdon 101 Mixture , a relative ly new commercial ly availabl e herbicid e, gave good results in the Lake States (Brinkm an, 1970) and the South (Voeller and Holt, 1973, Lawson and Ferguso n, 197 4). Either basal tube or hatchet in jectors may be used to apply it, and it has been hig hly effectiv e in both the dorman t and growin g seasons . Tordon 101 Mixture seems to ki ll more species than other injector -applied herbicid es.
As he rbicide results vary conside rably from one region to another because of differen t species and climate s, we conduc ted a series of tests on typical Kansas hardwo od species usually unwant ed in native black walnut stands.

The Studies and Early Results
We conducted studies on three sites the past three years within 50 miles of Topeka. Two were black walnut sapling-pole stands on intermittent streams while one was a larg e pole-small sawtimber cottonwood stand on the Kansas River.
In the first study the herbicide gave a high rate of kif!. It is too early to evaluate the last two, but good results are indicated now (Fa ll, 1975).
Detailed results are presented for the first study. It was in a typical eastern Kansas hardwood stand in Douglas County, about 10 miles south of Lawrence on a north facing slo pe overlooking an intermittent stream.
Eight species (375 trees) were injected with Tordon 101 Mixture 2 diluted with water 1:1 and injected through the bark at 3-inch intervals around the base of the tree with a Jim-Gem metering injector ( Figure 1 ). Approximately one milliliter of herbicide was injected into each cut (Figure 2) after the trees had leafed out fully in mid-May.
. Crown kill evaluations were made in mid-August the same year and in June the next year.
More than 95% of the injected trees had 100% crown kill the first year, with more the second year (Table 1 ). The few remaining treated trees had at least 50% crown kills. Only eight trees (2%) produced stem sprouts the second year.

Discu$sion
It appears that basal injected Tordon 101 Mixture will effectively control undesirable hardwood trees in eastern Kansas. Our resu lts ind ithat good crown kills without trunk sprout-Ing can be expected during the first growing season. Comparative trials of 2,4-D amine and Tordon 101 Mixture on a variety of hardwood species in the mountains of Arkansas have shown to be effective on a great number of species including some resistant to 2,4-D alone . Lawson, 1975, Voelle r andHolt, 1973). Tree ' species that we and others have cont rolled w ith To rdon 101 are listed in Table 2. Most of them are found in Kansas. Species showing greatest resistance to Tordon 101 Mixture we re b lack gum, sugar maple, and ashes.
Tordon 101 Mixture being water soluble improves its absorption into a tree's sap stream, that makes it d ifficult to use in winter. Tordon 1 0 l R, a new formulation commercially ava i 1able, overcomes that drawback.
Tree injection gradually releases desirable trees, while felling with a chainsaw immediately exposes "crop" trees to wind forces and would sti ll require stump spraying to kill the unwanted competitor.
In either case, immedia te or delayed felling many of the treated trees could be used as f irE;i. wood .   Information in this repo rt is for woodland owners, colleagues, industry coope rators, and other inte rested persons.
It is not a recommend ation, but re p resen ts two years' research at one loca tio n.
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