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. Invasive annual weeds including tumbleweeds and thistles were common in the plantations in <br />2005 and 2006, as well as numerous native herbaceous species. We controlled competing <br />vegetation in the irrigation and root-sprout treatments by repeatedly hoeing and cutting all weeds <br />growing around study trees. Landscape fabric placed around potted trees when they were planted <br />prevented weeds from growing next to those trees. The aggressive nature of weeds suggests that <br />vegetative competition may be important in survival and growth of aspen trees. The inability of <br />easily controlling competing vegetation with herbicides around broad-leaved species like aspen <br />presents additional constraints. <br />We investigated this question by continuing to mechanically control competing vegetation <br />around trees in half of each irrigation and soil treatment. Treatments in the fenced plantation area <br />were divided into sections to be weeded and sections not weeded. The two weeding treatments <br />were superimposed on the existing study design; and growth, physiological parameters, and <br />survival were compared as in other treatments. Soil samples were collected from each treatment <br />for moisture content analysis. <br />EXPERIMENTAL RESULTS <br />Aspen growth and survival on reclaimed lands was successful under certain conditions. The <br />experiment was conducted 2005-2007 on the II-W Mine plots, Seneca Coal Company, near <br />Hayden, CO (Figure 1). This report examined third year growth and survival of these trees. <br />Growth by irrigation treatments and plant type: <br />• Saline water inhibited the growth of aspen on high and medium irrigation treatment plots the first <br />and second year of the study. These trees were still smaller in the third year but their annual <br />growth had nearly recovered to that of low and control irrigation treatments (Figure 3). Growth <br />of the low irrigation and control (no irrigation) treatment trees was higher than that for the high <br />and medium irrigation treatments suggesting that the reduced growth from the saline water used <br />for irrigation in the first and second years of the experiment was still evident in the third year of <br />treatment. Nevertheless, growth of these trees was still greater than that for the natural sprouts <br />and potted trees. None of the trees that had died in previous years re-sprouted from residual roots <br />in 2007. Since growth of aspen was good with the low and no irrigation treatments, it is evident <br />that there was sufficient natural rainfall during the three years of the study for the trees to survive <br />without irrigation. It is possible that growth under the high irrigation treatment could have been <br />higher than the lower irrigation treatments had clean water been used. The benefit of clean water <br />irrigation of newly planted trees under more normal, low rainfall conditions could not be <br />determined in this experiment since low rainfall and drought conditions did not occur during the <br />study. <br />Growth of the transplanted trees was generally good during the third year of treatment and <br />surpassed that of the natural sprouts and potted trees (Figure 3). Survival was similar for all <br />transplants and natural sprouted trees (50-57%), but was considerably higher for potted plants <br />(80%). Growth and survival of the potted trees was excellent the first year of the study, but after <br />three years growth of the potted trees remained relatively stagnant and these trees were <br />considerably smaller than the transplanted trees. Growth of natural sprouts was also less than