Dear ECOLOG,
Thanks to several correspondents who helped me with my question about chlorosis in Pin Oaks (see below). The preferred hypothesis is that Pin Oaks rely on one/several mycorrhizal symbiont(s) to absorb iron (and perhaps other nutrients) from soil, especially in high-pH soils. Disturbed sites (e.g. in towns) may lack the fungi and/or conditions suitable to their growth. The following article describes a controlled experiment investigating the phenomenon: Hauer and Dawson: Chlorotic Pin Oak and Mycorrhizae. Journal of Arboriculture 22(3): May 1996 I still have questions, however, about why Pin oak symbionts are more sensitive to such altered conditions when other Oaks (or their symbionts) appear to be less affected. ---Paul Weihe ----- Original Message ----- From: "Paul Weihe" <wei...@central.edu> To: <ECOLOG-L@LISTSERV.UMD.EDU> Sent: Thursday, September 23, 2010 6:27 AM Subject: [ECOLOG-L] Pin oak root physiology Could anyone offer insight on the physiology of iron (or other similar nutrient) chlorosis? Specifically, why would a Pin Oak suffer the nutritional deficiency leading to chlorosis, and a Red Oak (or other species), growing in similar soil nearby, remain healthy? I do understand that higher pH relates to soil iron chemistry and subsequent uptake. But...why are two trees, both facing that constraint, reacting so differently? Any insight appreciated... --Paul Weihe
