Planted Shrub and Tree Report 2013

Planted Shrub and Tree Report 2013

March 7, 2014

Mike McTee reports on the ongoing tree and Shrub planting efforts at MPG Ranch. With an in-depth look at survivorship rates, comparison of outcomes between different irrigation techniques and species-location relationships, our understanding of how to effectively restore the Tree and Shrub populations is increasing with every season.

Planted Shrub and Tree Report 2013 Mike McTee Shrubs planted in 2012 (above) at Sheep Camp fill their exclosure a year later (below). In the forefront, a drip irrigated rabbitbrush burgeons.

Table of Contents: Cottonwood, aspen, and golden currant show their fall colors at the Upper Partridge spring.

Introduction This year’s shrub planting efforts included: • Planting bitterbrush, juniper, and mountain mahogany on the hottest, driest, and most eroded slopes at MPG. • Planting elderberry, limber pine, maple, and serviceberry in an upper elevation site • Expanding fruit orchards. • Extending a hedge row along the main road from the Top House to the Clubhouse...

South Facing Slope Revegetation Steep slopes, overgrazing, and overuse of the south facing slopes in the northern draws led to erosion. Little, if any, topsoil remains and few plants grow. Establishment of shrubs could decrease erosion. Aboveground biomass can catch eroding soils and provide shade, and may create microenvironments for other seedlings. In lower Sheep camp, Middle Draw, and Tongue Creek, we began efforts to stabilize slopes and establish plants. In spring 2013, Watershed Consulting installed erosion control bars to create terraces that catch eroding soils and provide a flat spot for shrub plantings. Hardy species with either high forage or cover value, such as bitterbrush, juniper, and mountain mahogany dominated the species list. The crew also planted wild rose, chokecherry, and rubber rabbitbrush. The MPG irrigation crew installed drip irrigation using water from the Sheep Camp stock tank system and new wells in Tongue Creek and Sheep Camp.

Northern Draws The table and map below indicate locations and shrub survivorship. The total dead count represents the number of trees that died in 2013. The “Alive (%)” column is the percent of trees that survived to the fall relative to the number of alive trees in the spring. Metrics below

Typical Planting Scheme for Northern Draws map and metrics below.

Survivorship: Northern Draws In Sheep Camp and Tongue Creek, we assigned Sheep shrubs to either receive drip irrigation Camp or not to test the drought tolerance of each shrub. Too few shrubs were planted in Middle Not Irrigated Irrigated Draw to provide a comparison, so all shrubs received irrigation.* At least 80% of junipers, irrigated and not irrigated, survived the summer in each location...

Height Increase: Northern Draws Methods and Results Percent height increase represents a shrub’s fall height relative to its spring height. For all percent increase figures and statistics, only shrubs with a height increase were included. Treatments with fewer than three shrubs showing a height increase were excluded from figures and analysis. Error bars represent standard error….

Middle Draw 2012-2013 Growth Rate Comparison In 2012, we planted shrubs and trees on the north facing slopes in the northern draws. Given the sites’ healthy soils and sun-protected aspects, we expected rapid growth. This year, height increases equaled or exceeded those of 2012 for most shrubs (figure below*). Buffaloberry and mountain mahogany flourished their second year. Being nitrogen-fixing shrubs, they will provide excellent browse for wildlife. Buffaloberry also forms thorny-thickets where birds nest and eat berries and wildlife find cover. Golden currant also exploded in growth, and within two years, will produce berries, outgrow their exclosures, and provide forage for passing wildlife. The reduction in the height increase between 2012 and 2013 for some species can be deceptive. When planted, elderberry consisted of several leaves just above ground level and most growth was vertical. This year, the plants may have put on more biomass than last year, but grew less vertically (relative to spring height as a percent), than the previous year.

Mountain Mahogany This mountain mahogany in Sheep Camp exemplifies the species’ rapid growth two seasons after planting. Red dashed lines approximate past heights based on mean height statistics from Middle Draw.

Survivorship: Woodchuck The same species planted in the northern draws were planted along a south facing slope in lower Woodchuck. Although south facing, the hill opposite the creek rises about 250 feet higher than the planted slope and can block direct sunlight longer than in the northern draws. Also, some intact topsoil and remnant grasses suggest a hospitable site. Survival rates were at or above 86% for all plantings–an exceptional rate relative to the northern draws. Rabbitbrush (bottom left) was planted in all sites but was excluded from previous figures due to low sample sizes.

Height Increase: Woodchuck Plants grew fast at this site. Bitterbrush height increased between 100% and 400%. The height measure does not account for branching, which may account for the majority of the plant’s biomass (photo: middle right). Juniper and mountain mahogany height increases ranged from no increase to about 100% increase. Height increases for rabbitbrush ranged from 38% to 467% percent. We planted this species last year, and where drip irrigated, the plant exploded in biomass. Although rabbitbrush produces only marginal forage, it can retain flowers into October and attracts late season pollinators. It grows in degraded habits, establishes a litter layer, and provides cover. We recognized the potential of this site to establish shrubs, so this fall we planted additional mountain mahogany. In spring 2014, we will increase shrub density.

Shrubs Reach Browse Height: Lower Woodchuck Creek Willows This year, many shrubs grew above their exclosures and were exposed to ungulate browse. In the spring and fall we measured willows planted in 2010 in lower Woodchuck Creek. Willows’ maximum heights fall within the browse range of a whitetail deer. The bottom red dotted line represents the exclosure height, and the top red dotted line represents the approximate maximum whitetail deer browse height (DNRC, Michigan). If browse pressure remains heavy, we would expect willow heights to reach the lower red dotted line and the height distribution to become narrow. As more shrubs grow above their exclosures, plant heights may be limited by browse. We will monitor browse in the 2014 season to determine which shrubs can outgrow browse height and which shrubs will require a taller exclosure...

Survivorship: Upper Partridge Alley Irrigating trees requires labor, supplies, and infrastructure maintenance. We tested whether drought tolerant species could establish without irrigation during their first year. In the spring, bitterbrush, juniper, and mountain mahogany were planted on the southern slope of upper Partridge Alley, tagged, and measured*. We returned in the fall to count dead and alive trees. Surviving trees were measured. Only 17% of bitterbrush and 7% of mountain mahogany (photo) survived the summer. Surviving mountain mahogany did not grow. These data suggest that bitterbrush and mountain mahogany should not be planted in the harshest sites without irrigation. Junipers showed the highest survival rate (48%). Junipers lose leaf pigment slowly as they die, so plants that were counted as alive may have been in the process of dying. A follow-up count in spring 2014 would inform us as to whether the junipers survived. If the 48% survival rate holds true, junipers could be planted in harsh soils and left.

Wirespool Junction Survivorship We explored which high value forage species could establish at higher elevations without irrigation. In the spring, near the Wirespool Junction, we planted elderberry, limber pine, rocky mountain maple, and serviceberry. We tagged trees in the spring and measured survivorship in the fall. Every elderberry and serviceberry survived. Limber pine and maple showed high and moderate survivorship, with 80% and 64%, respectively. The site faces the north-west so it is protected from direct sunlight, so soil desiccation should be less than much of the lowlands. Also, at an elevation of about 4600 feet, temperatures stay cooler and spring moisture can last longer into the summer. In 2013, the nearby North Draw weather station recorded nine inches of precipitation compared to six inches elsewhere at MPG. All these favorable conditions allowed these shrubs to survive without irrigation

Entrance Hedge and Partridge Hill Entrance Hedge and Partridge Hill were planted in 2010 and 2011 with high numbers of junipers and ponderosa pine. This site serves as a study area for several irrigation related treatments. The following pages detail our results. The map and table below indicate survivorship and locations of each area.

When Can Irrigation Cease? Eventually, plantings will grow well without irrigation. To test the irrigation dependence of junipers and ponderosa pines planted in 2010 and 2011, we removed drip emitters from trees chosen at random in the Entrance Hedge and Partridge Hill. We compared height increases from 2012 to 2013 for irrigated and not irrigated trees. Plant ages ranged from four to six years depending on their age at planting. Due to the possibility of plant mortality due to lack of water, we limited the “not irrigated” group to about 25% of the population. We retained all other drip irrigated trees in the “irrigated” group. Junipers grew faster when irrigated at both Entrance Hedge and Partridge Hill (F=22.3 and P<0.001; F=15.8 and P<0.001, respectively). Red stars in the figure represent significant differences at the P=0.05 level. Ponderosa pine increased in height at the same rate with and without water. Results indicate that water can be diverted away from ponderosa pines and directed to new plantings. Because irrigation increases the growth rate of junipers, we will continue to water that plant.

Growth Rate Comparisons We compared 2012 and 2013 growth rates of juniper and ponderosa pine at the Entrance Hedge and Partridge Hill using an Analysis of Variance (ANOVA). Ponderosa pines growing at the Entrance Hedge and Partridge Hill grew faster in 2013 than in 2012 (F=35.8 and P<0.001; F=8.7 and P<0.001, respectively). Metrics below.

Sample Sizes Metric

Plant Count Table 8 lists the total number of alive plantings at MPG in each location. Numbers in the “# on map” column correspond to the numbers on the next page. The total dead count represents the number of trees that died in 2013. The “Percent Alive” column is the percent of trees that survived to the fall relative to the number of alive trees in the spring.

Map of Locations

Related Research Reports

Bitterbrush Leader Growth Observations

January 9th, 2013
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2012 Planted Tree Report

November 29th, 2012
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