Terrain of Ribbon Ridge
The viticultural area is differentiated and separated from adjoining farming regions by the regularity and unaltered nature of its island-like ridge, its position as a separate land mass broken free from other uplifts or larger hillsides, and the clean division its drainage system makes around the full perimeter of the land mass. Specifically, the Chehalem Creek Valley is deep, wide, and severely sloped on Ribbon Ridge’s western flank. Where the Creek exits the hills, the Chehalem Valley is wide and flat at the 200-foot level to the south of Ribbon Ridge.
Dopp and Ayres Creeks originate on the flank of the Chehalem Mountains underneath Bald Peak, flowing westward to accumulate Ribbon Ridge’s drainage, and then diverging to the south and north, achieving the complete segregation of the ridge on the northwest side at an elevation of approximately 400 feet.
The viticultural area is defined as the area at 240 feet in elevation or above. From the air, it appears as an island that has broken off from the higher landmasses that surround it and floats freely above the Chehalem Valley floor. It extends southward from the Chehalem Mountains and rises above the floor of the Valley. Ribbon Ridge Road runs north to south along its spine. Ribbon Ridge is defined on the east and west by the watersheds that fall away from the road in both directions. It is separated from the Chehalem Mountains by Ayres Creek on the north and a creek known locally as Dopp Creek, which runs parallel to Dopp Road on the east and flows south to form the eastern boundary. On the western side of Ribbon Ridge, the Chehalem Creek Valley dramatically separates the viticultural area from the Coast Range hillsides that are associated with the Yamhill-Carlton District.
There is a gorge-like drop of 300 feet or more into the narrow quarter-mile ravine that widens at the foot of Ribbon Ridge into the broad, flat Chehalem Valley dividing the Chehalem Mountains from the Red Hills of Dundee area. This feature, more than any other, shows the separate nature of Ribbon Ridge’s formation as an uplifted landmass of unique origin.
Microclimate of Ribbon Ridge
Degree-day accumulations in the viticultural area average 2,455, as compared to 2,541 at McMinnville (southwest of Ribbon Ridge) and 2,650 at Portland (northeast of Ribbon Ridge) . Ribbon Ridge is typical of hillside sites with earlier starts to warming, less nighttime temperature drops, and clipped heat spikes in midsummer that provide a consistent climate for adequate ripening. These conditions allow longer, cooler growing seasons which are ideal for delicate varietals like Pinot Noir, Chardonnay, and Riesling. Ribbon Ridge’s island-like characteristics and the proximity of surrounding landmasses tend to shield and uniquely protect the viticultural area from many of the extremes that affect the other agricultural microclimates in the northern Willamette Valley. Air and water drainage exist on all sides. Low clouds tend to accumulate on the surrounding hilltops; fog tends to settle on the valley floor in the early and late parts of the growing season.
Soils
The soils of Ribbon Ridge are relatively uniform, all being marine sedimentary and fine textured at plantable elevations, without significant alterations from slides and erosion. Specifically, Ribbon Ridge is a distinct, natural, geological formation of eastward-tilted marine sedimentary strata dated to 40 to 50 million years ago. Because the ridge is ancient and stable, the soils from these fine sedimentary parent materials are well weathered and consequently are, on average, deeper in profile and more finely structured than soils in surrounding areas.
Unlike the Chehalem Mountains AVA and Yamhill-Carlton AVA , the soils of Ribbon Ridge are entirely derived from marine sedimentary parent materials. They are finer in average texture due to their finer parent materials of very fine sandstone, siltstone, and mudstone.
The soils generally exhibit good water-holding capability, but are not overly generous in nutrients, tending to restrain vine canopy vigor while maintaining good health, even in non-irrigated vineyards. Underground waters for irrigation and other large-scale uses are not readily available on Ribbon Ridge which tends to limit excess vine growth.